Organic light-emitting device

ABSTRACT

An organic light-emitting device having low-driving voltage, improved efficiency, and long lifespan includes: a first electrode; a second electrode facing the first electrode; a first layer between the first electrode and the second electrode, the first layer including a first compound; a second layer between the first layer and the second electrode, the second layer including a second compound; and a third layer between the second layer and the second electrode, the third layer including a third compound; wherein the first compound does not include a nitrogen-containing heterocyclic group comprising *═N—*′ as a ring forming moiety, and wherein the first compound, the second compound, and the third compound each independently include at least one group selected from groups represented by Formulae A to C:

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 15/242,040, filed Aug. 19, 2016, which claims priority to and the benefit of Korean Patent Application No. 10-2015-0118277, filed on Aug. 21, 2015 and Korean Patent Application No. 10-2016-0104281, filed on Aug. 17, 2016, the entire content of all of which is incorporated herein by reference.

BACKGROUND 1. Field

One or more aspects of example embodiments of the present disclosure relate to an organic light-emitting device.

2. Description of the Related Art

Organic light-emitting devices (OLEDs) are self-emission devices that have wide viewing angles, high contrast ratios, and short response times. In addition, the OLEDs exhibit excellent luminance, driving voltage, and response speed characteristics.

An OLED may include a first electrode disposed (e.g., positioned) on a substrate, and a hole transport region, an emission layer, an electron transport region, and a second electrode, which are sequentially disposed on the first electrode. Holes provided from the first electrode may move toward the emission layer through the hole transport region, and electrons provided from the second electrode may move toward the emission layer through the electron transport region. The holes and the electrons may then recombine in the emission layer to produce excitons. These excitons change from an excited state to a ground state to thereby generate light.

SUMMARY

One or more aspects of example embodiments of the present disclosure are directed toward an organic light-emitting device having low driving voltage, high efficiency, and long lifespan.

Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments.

According to one or more example embodiments, an organic light-emitting device includes a first electrode; a second electrode facing the first electrode; a first layer between the first electrode and the second electrode and including a first compound; a second layer between the first layer and the second electrode and including a second compound; and a third layer between the second layer and the second electrode and including a third compound,

wherein the first compound, the second compound, and the third compound may each independently include at least one group selected from groups represented by Formulae A to C, and the first compound does not include a nitrogen-containing heterocyclic group including *═N—*′ as a ring forming moiety:

wherein, in Formulae A to C,

ring A₁, ring A₁₁, and ring A₁₂ may be each independently selected from a C₅-C₃₀ carbocyclic group and a C₂-C₃₀ heterocyclic group, and

R₁, R₂, R₁₁, and R₁₂ may be each independently selected from:

hydrogen, deuterium, —F, —Cl, —Br, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, and a phosphoric acid group or a salt thereof;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group; and

—N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), and —B(Q₆)(Q₇),

wherein Q₁ to Q₇ may be each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group,

a1, a11, and a12 may be each independently an integer selected from 0 to 10,

a2 may be an integer selected from 0 to 2, and

wherein * and *′ each indicate a binding site to an adjacent atom.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readily appreciated from the following description of the example embodiments, taken in conjunction with the accompanying drawing, which is a schematic view of an organic light-emitting device according to an example embodiment.

DETAILED DESCRIPTION

Reference will now be made in more detail to example embodiments, examples of which are illustrated in the accompanying drawing, wherein like reference numerals refer to like elements throughout. In this regard, the present example embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the example embodiments are merely described below, by referring to the drawing, to explain aspects of the present description. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” “one of,” “at least one selected from,” and “one selected from,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. Further, the use of “may” when describing embodiments of the present invention refers to “one or more embodiments of the present invention.”

An organic light-emitting device may include: a first electrode; a second electrode facing the first electrode; a first layer between the first electrode and the second electrode and including a first compound; a second layer between the first layer and the second electrode and including a second compound; and a third layer between the second layer and the second electrode and including a third compound.

The first electrode may be an anode. The second electrode may be a cathode. Descriptions of the first electrode and the second electrode are as provided herein.

The first compound, the second compound, and the third compound may each independently include at least one group selected from groups represented by Formulae A to C, and

the first compound may not include a nitrogen-containing heterocyclic group including *═N—*′ as a ring forming moiety. As used herein, * and *′ may each indicate a binding site to a corresponding adjacent atom.

In Formulae A to C, ring A₁, ring A₁₁, and ring A₁₂ may be each independently selected from a C₅-C₃₀ carbocyclic group and a C₂-C₃₀ heterocyclic group.

In some embodiments, in Formulae A to C, ring A₁, ring A₁₁, and ring A₁₂ may be each independently selected from a benzene group, a naphthalene group, a fluorene group, a benzofluorene group, a pyridine group, a pyrimidine group, a carbazole group, a benzocarbazole group, and a dibenzothiophene group.

In Formulae A to C, R₁, R₂, R₁₁, and R₁₂ may be each independently selected from:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, and a phosphoric acid group or a salt thereof;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group; and

—N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), and —B(Q₆)(Q₇),

wherein Q₁ to Q₇ may be each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group.

In some embodiments, in Formulae A to C, R₁, R₂, R₁₁, and R₁₂ may be each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group;

a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, and a phosphoric acid group or a salt thereof;

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thienyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a benzoimidazolyl group, a benzofuranyl group, a benzothienyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothienyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group;

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thienyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a benzoimidazolyl group, a benzofuranyl group, a benzothienyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothienyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thienyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a benzoimidazolyl group, a benzofuranyl group, a benzothienyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothienyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, and —Si(Q₃₃)(Q₃₄)(Q₃₅), and

—N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), and —B(Q₆)(Q₇),

wherein Q₁ to Q₇ and Q₃₃ to Q₃₅ may be each independently selected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

In some embodiments, in Formulae A to C, R₁, R₂, R₁₁, and R₁₂ may be each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group;

a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, and a phosphoric acid group or a salt thereof;

a phenyl group, a biphenyl group, a terphenyl group, a fluorenyl group, a naphthyl group, a pyridinyl group, a pyrimidinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a quinazolinyl group, and a quinoxalinyl group;

a phenyl group, a biphenyl group, a terphenyl group, a fluorenyl group, a naphthyl group, a pyridinyl group, a pyrimidinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a quinazolinyl group, and a quinoxalinyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, and a C₆-C₁₆ aryl group; and

—N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), and —B(Q₆)(Q₇),

wherein Q₁ to Q₇ may be each independently selected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a fluorenyl group, and a naphthyl group, but embodiments of the present disclosure are not limited thereto.

In Formulae A to C, a1, a11, and a12 may be each independently an integer selected from 0 to 10, and a2 may be an integer selected from 0 to 2.

a1 in Formula A indicates the number of R₁(s). When a1 is 2 or more, a plurality of R₁(s) may be identical to or different from each other. a2, a11, and a12 may be each independently understood by referring to the description of a1 and the structures of corresponding Formulae B and C.

In some embodiments, in Formulae A to C, a1, a11, and a12 may be each independently an integer selected from 0 to 8, and a2 may be an integer selected from 0 to 2.

In Formulae A to C, * indicates a binding site to an adjacent atom.

In some embodiments, the first compound, the second compound, and the third compound may each independently include at least one group represented by Formulae A(1), A(2), B(1) to B(4), and C(1) to C(16):

wherein, in Formulae A(1), A(2), B(1) to B(4), and C(1) to C(16),

descriptions of R_(1a) to R_(1d) may be each independently the same as the description provided in connection with R₁,

descriptions of R_(2a) and R_(2b) may be each independently the same as the description provided in connection with R₂,

descriptions of R_(11a) and R_(11h) may be each independently the same as the description provided in connection with R₁₁,

descriptions of R_(12a) to R_(12d) may be each independently the same as the description provided in connection with R₁₂, and

* indicates a binding site to an adjacent atom.

In some embodiments, in Formulae A(1), A(2), B(1) to B(4), and C(1) to C(16),

R_(1a) to R_(1d), R_(2a), R_(2b), R_(11a) to R_(11h), and R_(12a) to R_(12d) may be each independently selected from:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group;

a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, and a phosphoric acid group or a salt thereof;

a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group;

a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, and a naphthyl group; and

—N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), and —B(Q₆)(Q₇),

wherein Q₁ to Q₇ may each independently be selected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

According to an embodiment, the first compound may be selected from compounds represented by Formulae 1-1 to 1-3,

the second compound may be selected from compounds represented by Formulae 2H-1, 2D-1, and 2D-2, and

the third compound may include a nitrogen-containing heterocyclic group including *═N—*′ as a ring forming moiety and may be selected from compounds represented by Formulae 3-1 and 3-2:

In Formula 3-1,

X₁ may be C(R₄₁) or N,

X₂ may be C(R₄₂) or N, and

X₃ may be C(R₄₃) or N.

In some embodiments, in Formula 3-1, X₁ may be C(R₄₁), X₂ may be C(R₄₂), and X₃ may be C(R₄₃). In this case, at least one of Ar₄₁ to Ar₄₃ may include a nitrogen-containing heterocyclic group including *═N—*′ as a ring forming moiety.

In some embodiments, in Formula 3-1, at least one of X₁ to X₃ may be nitrogen (N).

In some embodiments, in Formula 3-1, X₁ to X₃ may each be N.

In Formula 3-1, R₄₁ to R₄₃ may be each independently understood by referring to the descriptions thereof provided herein.

In Formulae 1-1, 1-2, 1-3, 2H-1, 2D-1, 2D-2, 3-1, and 3-2,

L₂₁ to L₂₄, L₃₁ to L₃₄, and L₄₁ to L₄₃ may be each independently selected from a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group.

In some embodiments, in Formulae 1-1, 1-2, 1-3, 2H-1, 2D-1, 2D-2, 3-1, and 3-2,

L₂₁ to L₂₄, L₃₁ to L₃₄, and L₄₁ to L₄₃ may be each independently selected from a phenylene group, a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an indacenylene group, an acenaphthylene group, a fluorenylene group, a spiro-fluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a rubicenylene group, a coronenylene group, an ovalenylene group, a pyrrolylene group, a thienylene group, a furanylene group, an imidazolylene group, a pyrazolylene group, a thiazolylene group, an isothiazolylene group, an oxazolylene group, an isoxazolylene group, a pyridinylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, an isoindolylene group, an indolylene group, an indazolylene group, a purinylene group, a quinolinylene group, an isoquinolinylene group, a benzoquinolinylene group, a phthalazinylene group, a naphthyridinylene group, a quinoxalinylene group, a quinazolinylene group, a cinnolinylene group, a carbazolylene group, a phenanthridinylene group, an acridinylene group, a phenanthrolinylene group, a phenazinylene group, a benzoimidazolylene group, a benzofuranylene group, a benzothienylene group, an isobenzothiazolylene group, a benzoxazolylene group, an isobenzoxazolylene group, a triazolylene group, a tetrazolylene group, an oxadiazolylene group, a triazinylene group, a dibenzofuranylene group, a dibenzothienylene group, a benzocarbazolylene group, a dibenzocarbazolylene group, a thiadiazolylene group, an imidazopyridinylene group, and an imidazopyrimidinylene group; and

a phenylene group, a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an indacenylene group, an acenaphthylene group, a fluorenylene group, a spiro-fluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a rubicenylene group, a coronenylene group, an ovalenylene group, a pyrrolylene group, a thienylene group, a furanylene group, an imidazolylene group, a pyrazolylene group, a thiazolylene group, an isothiazolylene group, an oxazolylene group, an isoxazolylene group, a pyridinylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, an isoindolylene group, an indolylene group, an indazolylene group, a purinylene group, a quinolinylene group, an isoquinolinylene group, a benzoquinolinylene group, a phthalazinylene group, a naphthyridinylene group, a quinoxalinylene group, a quinazolinylene group, a cinnolinylene group, a carbazolylene group, a phenanthridinylene group, an acridinylene group, a phenanthrolinylene group, a phenazinylene group, a benzoimidazolylene group, a benzofuranylene group, a benzothienylene group, an isobenzothiazolylene group, a benzoxazolylene group, an isobenzoxazolylene group, a triazolylene group, a tetrazolylene group, an oxadiazolylene group, a triazinylene group, a dibenzofuranylene group, a dibenzothienylene group, a benzocarbazolylene group, a dibenzocarbazolylene group, a thiadiazolylene group, an imidazopyridinylene group, and an imidazopyrimidinylene group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an am idino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group, a thienyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, a benzofuranyl group, a benzothienyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothienyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, and —Si(Q₃₃)(Q₃₄)(Q₃₅), and

descriptions of Q₃₃ to Q₃₅ may be each independently understood by referring to the description of Q₁ provided herein.

In Formula 1-2, L₂₅ may be selected from a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ non-condensed arylene group, and a substituted or unsubstituted C₁-C₆₀ non-condensed heteroarylene group.

In some embodiments, in Formula 1-2, L₂₅ may be selected from:

a phenylene group; and

a phenylene group substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, C₁-C₂₀ alkyl group, and C₁-C₂₀ alkoxy group.

In Formula 2D-1, L₃₅ may be selected from a substituted or unsubstituted C₆-C₆₀ condensed polycyclic arylene group, a substituted or unsubstituted C₁-C₆₀ condensed polycyclic heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group.

In some embodiments, in Formula 2D-1, L₃₅ may be selected from:

a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an indacenylene group, an acenaphthylene group, a fluorenylene group, a spiro-fluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a rubicenylene group, a coronenylene group, an ovalenylene group, an isoindolylene group, an indolylene group, an indazolylene group, a purinylene group, a quinolinylene group, an isoquinolinylene group, a benzoquinolinylene group, a phthalazinylene group, a naphthyridinylene group, a quinoxalinylene group, a quinazolinylene group, a cinnolinylene group, a carbazolylene group, a phenanthridinylene group, an acridinylene group, a phenanthrolinylene group, a phenazinylene group, a benzoimidazolylene group, a benzofuranylene group, a benzothienylene group, an isobenzothiazolylene group, a benzoxazolylene group, an isobenzoxazolylene group, an oxadiazolylene group, a dibenzofuranylene group, a dibenzothienylene group, a benzocarbazolylene group, a dibenzocarbazolylene group, an imidazopyridinylene group, and an imidazopyrimidinylene group; and

a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an indacenylene group, an acenaphthylene group, a fluorenylene group, a spiro-fluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a rubicenylene group, a coronenylene group, an ovalenylene group, an isoindolylene group, an indolylene group, an indazolylene group, a purinylene group, a quinolinylene group, an isoquinolinylene group, a benzoquinolinylene group, a phthalazinylene group, a naphthyridinylene group, a quinoxalinylene group, a quinazolinylene group, a cinnolinylene group, a carbazolylene group, a phenanthridinylene group, an acridinylene group, a phenanthrolinylene group, a phenazinylene group, a benzoimidazolylene group, a benzofuranylene group, a benzothienylene group, an isobenzothiazolylene group, a benzoxazolylene group, an isobenzoxazolylene group, an oxadiazolylene group, a dibenzofuranylene group, a dibenzothienylene group, a benzocarbazolylene group, a dibenzocarbazolylene group, an imidazopyridinylene group, and an imidazopyrimidinylene group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group.

In Formulae 1-1, 1-2, 1-3, 2D-1, 2D-2, 3-1, and 3-2, b1 to b5, d1 to d5, and g1 to g3 may be each independently an integer selected from 0 to 3.

b1 indicates the number of L₂₁(s) in Formulae 1-1 to 1-3. When b1 is 0, *-(L₂₁)_(b1)-*′ may be a single bond. When b1 is 2 or more, a plurality of L₂₁(s) may be identical to or different from each other. b2 to b5 may be each independently understood by referring to the descriptions of b1 and the corresponding structures of Formulae 1-1 to 1-3.

d1 indicates the number of L₃₁(s) in Formulae 2D-1 and 2D-2. When d1 is 0, *-(L₃₁)_(d1)-*′ may be a single bond. When d1 is 2 or more, a plurality of L₃₁(s) may be identical to or different from each other. d2 to d5 may be each independently understood by referring to the descriptions of d1 and the corresponding structures of Formulae 2D-1 and 2D-2.

g1 indicates the number of L₄₁(s) in Formulae 3-1 to 3-2. When g1 is 0, *-(L₄₁)_(g1)-*′ may be a single bond. When g1 is 2 or more, a plurality of L₄₁(s) may be identical to or different from each other. g2 and g3 may be each independently understood by referring to the descriptions of g1 and the corresponding structures of Formulae 3-1 to 3-3.

In Formulae 1-1, 1-2, 1-3, 2H-1, 2D-1, 2D-2, 3-1, and 3-2,

Ar₂₁ to Ar₂₄, Ar₃₁ to Ar₃₄, and Ar₄₁ to Ar₄₃ may be each independently a group selected from groups represented by Formulae A to C, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a biphenyl group, a terphenyl group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group.

In some embodiments, in Formulae 1-1, 1-2, 1-3, 2H-1, 2D-1, 2D-2, 3-1, and 3-2, Ar₂₁ to Ar₂₄, Ar₃₁ to Ar₃₄, and Ar₄₁ to Ar₄₃ may be each independently:

a group selected from groups represented by Formulae A to C;

a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group, a thienyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, a benzofuranyl group, a benzothienyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothienyl group, a benzocarbazolyl group, a dibenzocarbazolyl group a dibenzosilolyl group, a thiadiazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group; and

a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group, a thienyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, a benzofuranyl group, a benzothienyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothienyl group, a benzocarbazolyl group, a dibenzocarbazolyl group a dibenzosilolyl group, a thiadiazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group, a thienyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, a benzofuranyl group, a benzothienyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothienyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, and —Si(Q₃₃)(Q₃₄)(Q₃₅),

wherein Q₃₃ to Q₃₅ may be each independently understood by referring to the descriptions thereof provided herein.

In Formulae 1-3, 2H-1, 3-1, and 3-2,

R₂₁ to R₂₄, R₃₁, and R₄₁ to R₄₄ may be each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, and —Si(Q₄₃)(Q₄₄)(Q₄₅), where Q₄₃ to Q₄₅ may be each independently understood by referring to the description of Q₁ provided herein.

In some embodiments, in Formulae 1-3, 2H-1, 3-1, and 3-2,

R₂₁ to R₂₄, R₃₁, and R₄₁ to R₄₄ may be each independently selected from:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group;

a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, and a phosphoric acid group or a salt thereof;

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thienyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a benzoimidazolyl group, a benzofuranyl group, a benzothienyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothienyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group;

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thienyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a benzoimidazolyl group, a benzofuranyl group, a benzothienyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothienyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an am idino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thienyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a benzoimidazolyl group, a benzofuranyl group, a benzothienyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothienyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, and —Si(Q₃₃)(Q₃₄)(Q₃₅), and

—Si(Q₄₃)(Q₄₄)(Q₄₅), where Q₃₃ to Q₃₅ and Q₄₃ to Q₄₅ are as defined herein.

In Formulae 1-3, 2H-1, and 3-2,

c1, c4, h1, and h4 may be each independently an integer selected from 0 to 4, e1 may be an integer selected from 0 to 7, and c2, c3, h2, and h3 may be each independently an integer selected from 0 to 3.

c1 indicates the number of R₂₁(s) in Formula 1-3. When c1 is 2 or more, a plurality of R₂₁(s) may be identical to or different from each other. c2 to c4 may be each independently understood by referring to the description of c1 and the corresponding structure of Formula 1-3.

e1 indicates the number of R₃₁(s) in Formula 2H-1. When e1 is 2 or more, a plurality of R₃₁(s) may be identical to or different from each other.

h1 indicates the number of R₄₁(s) in Formula 3-2. When h1 is 2 or more, a plurality of R₄₁(s) may be identical to or different from each other. h2 to h4 may be each independently understood by referring to the description of h1 and the corresponding structure of Formula 3-2.

In some embodiments, in Formula 1-1, at least one of Ar₂₁ to Ar₂₃ may be a group selected from groups represented by Formulae A to C,

in Formula 1-2, at least one of Ar₂₁ to Ar₂₄ may be a group selected from groups represented by Formulae A to C,

in Formula 1-3, at least one of Ar₂₁ and Ar₂₂ may be a group selected from groups represented by Formulae A to C,

in Formula 2H-1, Ar₃₁ may be a group selected from groups represented by Formulae A to C,

in Formula 2D-1, at least one of Ar₃₁ to Ar₃₄ may be a group selected from groups represented by Formulae A to C,

in Formula 2D-2, at least one of Ar₃₁ to Ar₃₃ may be a group selected from groups represented by Formulae A to C, provided that the group selected from Formulae A to C included in Formula 2D-2 includes —N(Q₁)(Q₂) (where Q₁ and Q₂ may be understood by referring to the descriptions thereof provided herein),

in Formula 3-1, at least one of Ar₄₁ to Ar₄₃ may be a group selected from groups represented by Formulae A to C, and

in Formula 3-2, one of Ar₄₁ and Ar₄₂ may be a group selected from groups represented by Formulae A to C, and the other one of Ar₄₁ and Ar₄₂ may be a nitrogen-containing heterocyclic group including *═N—*′ as a ring-forming moiety.

In some embodiments, compounds represented by Formulae 1-1, 1-2, 1-3, 2H-1, 2D-1, 2D-2, 3-1, and 3-2 may include a group selected from groups represented by Formulae A to C.

According to an embodiment of the present disclosure, the first compound may be selected from compounds represented by Formulae 1-1(1) to 1-1(4), 1-2(1), and 1-3(1),

the second compound may be selected from compounds represented by Formulae 2H-1(1) to 2H-1(4), 2D-1(1) to 2D-1(4), 2D-2(1), and 2D-2(2), and

the third compound may be selected from compounds represented by Formulae 3-1(1), 3-1(2), and 3-2(1):

In Formulae 1-1(1) to 1-1(4), 1-2(1), 1-3(1), 2H-1(1) to 2H-1(4), 2D-1(1) to 2D-1(4), 2D-2(1), 2D-2(2), 3-1(1), 3-1(2), and 3-2(1),

L₂₁ to L₂₄, L₃₁ to L₃₄, L₄₁ to L₄₃, b1 to b5, d1 to d4, g1 to g3, Ar₂₁ to Ar₂₄, Ar₃₁ to Ar₃₄, Ar₄₁ to Ar₄₃, R₂₁ to R₂₄, R₃₁, R₄₁ to R₄₄, c1 to c4, e1, h1 to h4, Q₁, and Q₂ may be understood by referring to the descriptions thereof provided herein.

In Formulae 1-1(1) to 1-1(4), 2D-1(1) to 2D-1(4), 2D-2(1), and 2D-2(2), Z₁ to Z₅ may be each independently selected from:

deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, and —Si(Q₁₃)(Q₁₄)(Q₁₅),

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, and —Si(Q₂₃)(Q₂₄)(Q₂₅); and

—Si(Q₃₃)(Q₃₄)(Q₃₅)

Q₁, Q₂, Q₁₃ to Q₁₅, Q₂₃ to Q₂₅, and Q₃₃ to Q₃₅ may be understood by referring to the descriptions thereof provided herein.

In Formulae 1-1(1) to 1-1(4), 2D-1(1) to 2D-1(4), 2D-2(1), and 2D-2(2), f1 may be an integer selected from 0 to 4, f2 may be an integer selected from 0 to 3, f3 may be an integer selected from 0 to 5, and f4 may be an integer selected from 0 to 2.

In Formula 1-1(1), at least one of Ar₂₂ and Ar₂₃ may be a group selected from groups represented by Formulae A to C,

in Formula 1-1(2), at least one of Ar₂₂ and Ar₂₃ may be a group selected from groups represented by Formulae A to C,

in Formula 1-1(3), at least one of Ar₂₁ to Ar₂₃ may be a group selected from groups represented by Formulae A to C,

in Formula 1-1(4), at least one of Ar₂₁ to Ar₂₃ may be a group selected from groups represented by Formulae A to C,

in Formula 1-2(1), at least one of Ar₂₁ to Ar₂₄ may be a group selected from groups represented by Formulae A to C,

in Formula 1-3(1), at least one of Ar₂₁ and Ar₂₂ may be a group selected from groups represented by Formulae A to C,

in Formulae 2H-1(1) to 2H-1(4), Ar₃₁ may be a group selected from groups represented by Formulae A to C,

in Formula 2D-1(1), at least one of Ar₃₁ to Ar₃₄ may be a group selected from groups represented by Formulae A to C,

in Formula 2D-1(2), at least one of Ar₃₁ to Ar₃₄ may be a group selected from groups represented by Formulae A to C,

in Formula 2D-1(3), at least one of Ar₃₁ to Ar₃₄ may be a group selected from groups represented by Formulae A to C,

in Formula 2D-1(4), at least one of Ar₃₁ to Ar₃₄ may be a group selected from groups represented by Formulae A to C,

in Formula 2D-2(1), at least one of Ar₃₂ and Ar₃₃ may be a group selected from groups represented by Formulae A to C,

in Formula 2D-2(2), at least one of Ar₃₂ and Ar₃₃ may be a group selected from groups represented by Formulae A to C,

in Formula 3-1(1), at least one of Ar₄₁ to Ar₄₃ may be a group selected from groups represented by Formulae A to C,

in Formula 3-1(2), at least one of Ar₄₁ to Ar₄₃ may be a group selected from groups represented by Formulae A to C, and

in Formula 3-2(1), one of Ar₄₁ and Ar₄₂ may be a group selected from groups represented by Formulae A to C, and the other one of Ar₄₁ and Ar₄₂ may be a nitrogen-containing heterocyclic group including *═N—*′ as a ring forming moiety.

In some embodiments, compounds represented by Formulae 1-1(1) to 1-1(4), 1-2(1), 1-3(1), 2H-1(1) to 2H-1(4), 2D-1(1) to 2D-1(4), 2D-2(1), 2D-2(2), 3-1(1), 3-1(2), and 3-2(1) may include a group selected from Formulae A to C (e.g., a group selected from groups represented by Formulae A to C included as a major component).

According to one or more example embodiments, an organic light-emitting device may include:

a first compound selected from Compounds 1-1 to 1-12 and 2-1 to 2-10;

a second compound selected from Compounds 3-1 to 3-12 and 4-1 to 4-12; and

a third compound selected from Compounds 5-1 to 5-9:

At least two selected from the first compound, the second compound, and the third compound may have a triplet energy of 2.4 eV or more, for example, 2.5 eV or more. When the triplet energy is within these ranges, in a fluorescent organic light-emitting device, for example, emission efficiency through the triplet-triplet fusion (TTF) may be improved, and in a phosphorescent organic light-emitting device, the transfer of triplet excitons formed in an emission layer may be suppressed or reduced, thereby preventing or reducing a decrease in device efficiency.

In some embodiments, each of the first compound, the second compound, and the third compound may have asymmetrical structure.

For example: in Formula 1-1, a case where -(L₂₁)_(b1)-Ar₂₁, -(L₂₂)_(b2)-Ar₂₂, and -(L₂₃)_(b3)-Ar₂₃ are the same may be excluded; in Formula 1-2, a case where -(L₂₁)_(b1)-Ar₂₁, -(L₂₂)_(b2)-Ar₂₂, -(L₂₃)_(b3)-Ar₂₃, and -(L₂₄)_(b4)-Ar₂₄ are the same may be excluded; in Formula 2D-1, a case where -(L₃₁)_(d1)-Ar₃₁, -(L₃₂)_(d2)-Ar₃₂, -(L₃₃)_(d3)-Ar₃₃, and -(L₃₄)_(d4)-Ar₃₄ are the same may be excluded; in Formula 2D-2, a case where -(L₃₁)_(d1)-Ar₃₁, -(L₃₂)_(d2)-Ar₃₂, and -(L₃₃)_(d3)-Ar₃₃ are the same may be excluded and in Formula 3-1, a case where -(L₄₁)_(g1)-Ar₄₁, -(L₄₂)_(g2)-Ar₄₂, and -(L₄₃)_(g3)-Ar₄₃ are the same may be excluded.

In some embodiments, in Formula 1-3, the two carbazole moieties coupled via -(L₂₃)_(b3)- may be different from each other; in Formula 2H-1, (R₃₁)_(e1) and Ar₃₁ coupled via -(L₃₁)- may be different from each other; and in Formula 3-2, the two carbazole moieties coupled via -(L₄₃)_(g3)- may be different from each other.

When each of the first compound, the second compound, and the third compound has an asymmetrical structure as described above, for example, the level of stacking and aggregation of molecules in an organic layer may decrease. Therefore, for example, when each of the first compound, the second compound, and the third compound is used as a matrix material in a layer including the compound, degradation of the device may be prevented or reduced and the lifespan of the device may improve.

According to an embodiment of the present disclosure, the first compound may be selected from compounds represented by Formulae 1-1 to 1-3,

the second compound may be represented by Formula 2H-1, and

the third compound may be selected from compounds represented by Formulae 3-1 and 3-2.

In some embodiments, the first compound may be selected from compounds represented by Formulae 1-1(1) to 1-1(4), 1-2(1), and 1-3(1),

the second compound may be selected from compounds represented by Formulae 2H-1(1) to 2H-1(4), and

the third compound may be selected from compounds represented by Formulae 3-1(1), 3-1(2), and 3-2(1).

According to one or more example embodiments, in an organic light-emitting device, a second layer may be an emission layer and may further include a dopant, in addition to the compounds described above, and

a first layer and a third layer may each directly contact the second layer.

In some embodiments, the dopant may be a phosphorescent dopant. Non-limiting examples of the dopant will be described below.

According to an embodiment of the present disclosure, the first compound may be selected from compounds represented by Formulae 1-1 to 1-3,

the second compound may be selected from compounds represented by Formulae 2D-1 and 2D-2, and

the third compound may be selected from compounds represented by Formulae 3-1 and 3-2.

In some embodiments, the first compound may be selected from compounds represented by Formulae 1-1(1) to 1-1(4), 1-2(1), and 1-3(1),

the second compound may be selected from compounds represented by Formulae 2D-1(1) to 2D-1(4), 2D-2(1), and 2D-2(2), and

the third compound may be selected from compounds represented by Formulae 3-1(1), 3-1(2), and 3-2(1).

According to one or more example embodiments, in an organic light-emitting device,

the second layer may be an emission layer, and the second layer may further include a host, in addition to the compounds described above, and

a first layer and a third layer may each directly contact the second layer.

In some embodiments, the host may be a fluorescent host. Non-limiting examples of the host will be described below.

In some embodiments, the first compound and the second compound may be each independently selected from compounds represented by Formulae 1-1, 1-2, and 1-3,

where the first compound may be different from the second compound, and

the third compound may be selected from compounds represented by Formulae 2H-1, 2D-1, 2D-2, 3-1, and 3-2.

In some embodiments, the first compound and the second compound may be each independently selected from compounds represented by Formulae 1-1(1) to 1-1(4), 1-2(1), and 1-3(1),

where the first compound may be different from the second compound, and

the third compound may be selected from compounds represented by Formulae 2H-1(1) to 2H-1(4), 2D-1(1) to 2D-1(4), 2D-2(1), 2D-2(2), 3-1(1), 3-1(2), and 3-2(1).

In some embodiments,

the first compound and the second compound may be each independently selected from compounds represented by Formulae 1-1, 1-2, and 1-3,

where the first compound may be different from the second compound, and

the third compound may be selected from compounds represented by Formulae 2H-1, 3-1 and 3-2.

In some embodiments, the first compound and the second compound may be each independently selected from compounds represented by Formulae 1-1(1) to 1-1(4), 1-2(1), and 1-3(1),

where the first compound may be different from the second compound, and

the third compound may be selected from compounds represented by Formulae 2H-1(1) to 2H-1(4), 3-1(1), 3-1(2), and 3-2(1).

An organic light-emitting device according to another example embodiment may include the third layer as an emission layer, the third layer further including a dopant, in addition to the compounds described above, and the second layer may directly contact the third layer. In some embodiments, the dopant may be a phosphorescent dopant.

In some embodiments, the first compound and the second compound may be each independently selected from compounds represented by Formulae 1-1, 1-2, and 1-3,

where the first compound may be different from the second compound, and

the third compound may be selected from compounds represented by Formulae 2D-1, 2D-2, 3-1 and 3-2.

In some embodiments, the first compound and the second compound may be each independently selected from compounds represented by Formulae 1-1(1) to 1-1(4), 1-2(1), and 1-3(1),

where the first compound may be different from the second compound, and

the third compound may be selected from compounds represented by Formulae 2D-1(1) to 2D-1(4), 2D-2(1), 2D-2(2), 3-1(1), 3-1(2), and 3-2(1).

An organic light-emitting device according to another example embodiment may include the third layer as an emission layer, the third layer further including a host, in addition to the compounds described above, and the second layer may directly contact the third layer. In some embodiments, the host may be a fluorescent host.

The first compound and the second compound may be each independently selected from Compounds 1-1 to 1-12 and 2-1 to 2-10,

where the first compound may be different from the second compound, and

the third compound may be selected from Compounds 3-1 to 3-12, 4-1 to 4-12, and 5-1 to 5-9.

The organic light-emitting device may include the first layer including the first compound, the second layer including the second compound, and the third layer including the third compound, wherein each of the first compound, the second compound, and the third compound may include at least one group selected from Formulae A to C. Accordingly, charge transfer may be facilitated due to the similarity in molecular structures of the first, second, and third compounds. Further, the interfacial characteristics between the three layers may improve, thereby improving the stability and lifespan of the organic light-emitting device.

Hereinafter a structure and a method of manufacturing an organic light-emitting device according to one or more embodiments of the present disclosure will be described with reference to the drawing.

The drawing is a schematic cross-sectional view of an organic light-emitting device (OLED) 10 according to an example embodiment of the present disclosure.

The OLED 10 may include a first electrode 110, a first layer 130, a second layer 150, and a third layer 170, and a second electrode 190, which are sequentially layered in the stated order.

Referring to the drawing, a substrate may be additionally disposed (e.g., positioned) under the first electrode 110 or on the second electrode 190. The substrate may be a glass substrate or transparent plastic substrate, each with excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and/or water resistance.

The first electrode 110 may be formed by depositing or sputtering a material for forming the first electrode 110 on the substrate. When the first electrode 110 is an anode, the material for forming the first electrode 110 may be selected from materials with a high work function that facilitate hole injection. The first electrode 110 may be a reflective electrode, a semi-transmissive electrode, or a transmissive electrode. The material for forming the first electrode 110 may be a transparent and highly conductive material. Non-limiting examples of such material may include indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO₂), and zinc oxide (ZnO). When the first electrode 110 is a semi-transmissive electrode or a reflective electrode, as a material for forming the first electrode 110, at least one selected from magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), and magnesium-silver (Mg—Ag) may be used.

The first electrode 110 may have a single-layer structure, or a multi-layer structure including a plurality of layers. For example, the first electrode 110 may have a triple-layer structure of ITO/Ag/ITO, but embodiments of the present disclosure are not limited thereto.

The first layer 130, the second layer 150, and the third layer 170 may be sequentially stacked on the first electrode 110.

The first layer 130 may include a first compound, the second layer 150 may include a second compound, and the third layer 170 may include a third compound. The descriptions of the first to third compounds may be understood by referring to the descriptions thereof provided herein.

Although not illustrated in the drawing, a hole injection layer may be additionally disposed (e.g., positioned) between the first electrode 110 and the first layer 130.

When the organic light-emitting device 10 includes a hole injection layer, the hole injection layer may be formed on the first electrode 110 by using one or more suitable methods, such as vacuum deposition, spin coating, casting, a Langmuir-Blodgett (LB) method, ink-jet printing, laser printing, and/or laser-induced thermal imaging (LITI).

When the hole injection layer is formed by vacuum deposition, for example, the vacuum deposition may be performed at a temperature of about 100° C. to about 500° C., at a vacuum degree of about 10⁻⁸ Torr to about 10⁻³ Torr, and at a vacuum deposition rate in a range of about 0.01 Å/sec to about 100 Å/sec, depending on the compound for forming the hole injection layer, and the structure of the hole injection layer to be formed.

When a hole injection layer is formed by spin coating, the spin coating may be performed at a coating rate of about 2000 rpm to about 5000 rpm, and at a temperature of about 80° C. to 200° C., depending on the compound for forming the hole injection layer, and the structure of the hole injection layer to be formed.

The thickness of the hole injection layer may be in a range of about 100 Å to about 10,000 Å, for example, about 100 Å to about 1,000 Å.

The method of forming the hole injection layer may be understood by referring to any of the methods of forming the first layer 130, the second layer 150, and the third layer 170.

In some embodiments, the first layer 130 may include the first compound, and may additionally include at least one selected from m-MTDATA, TDATA, 2-TNATA, NPB, β-NPB, TPD, a spiro-TPD, a spiro-NPB, methylated NPB, TAPC, HMTPD, 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA), polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS), polyaniline/camphor sulfonic acid (PANI/CSA), and (polyaniline)/poly(4-styrenesulfonate) (PANI/PSS):

The first layer 130 may further include a charge-generating material, in addition to the materials mentioned above, to improve conductive properties. The charge-generating material may be homogeneously or non-homogeneously dispersed throughout the first layer 130.

The charge-generating material may be, for example, a p-dopant. The p-dopant may be selected from a quinone derivative, a metal oxide, and a cyano group-containing compound, but embodiments of the present disclosure are not limited thereto. Non-limiting examples of the p-dopant may include quinone derivatives (such as tetracyanoquinonedimethane (TCNQ) and/or Compound HT-D2); metal oxides (such as tungsten oxide and/or molybdenum oxide); and Compound HT-D1, but embodiments are not limited thereto.

In some embodiments, the first layer 130 may be a hole transport layer. When the first layer 130 is a hole transport layer, the thickness of the hole transport layer may be in a range of about 50 Å to about 2,000 Å, for example, about 100 Å to about 1,500 Å.

According to an embodiment, the second layer 150 may be an emission layer, and the first layer 130 and the third layer 170 may each directly contact the second layer 150.

In some embodiments, the third layer 170 may be an emission layer, and the second layer 150 may directly contact the third layer 170.

When the organic light-emitting device 10 is a full color organic light-emitting device, the emission layer may be patterned into a red emission layer, a green emission layer, or a blue emission layer, according to a sub-pixel. In some embodiments, the emission layer may have a stacked structure of a red emission layer, a green emission layer, and a blue emission layer, or may include a red-light emission material, a green-light emission material, and a blue-light emission material, which are mixed with each other in a single layer, to emit white light.

In some embodiments, when the second layer 150 is an emission layer, the emission layer may include the second compound, and may additionally include a host and/or a dopant.

In some embodiments, when the third layer 170 is an emission layer, the emission layer may include the third compound, and may additionally include a host and/or a dopant.

The host may include a compound represented by Formula 301:

Ar₃₀₁-[(L₃₀₁)_(xb1)-R₃₀₁]_(xb2).  Formula 301

In Formula 301,

Ar₃₀₁ may be selected from:

a naphthalene group, a heptalene group, a fluorene group, a spiro-fluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentaphene group, and an indenoanthracene group; and

a naphthalene group, a heptalene group, a fluorene group, a spiro-fluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentaphene group, and an indenoanthracene group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, and —Si(Q₃₀₁)(Q₃₀₂)(Q₃₀₃), wherein Q₃₀₁ to Q₃₀₃ may be each independently selected from hydrogen, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₆-C₆₀ aryl group, and a C₁-C₆₀ heteroaryl group,

description of L₃₀₁ may be the same as the description provided in connection with L₂₁,

R₃₀₁ may be selected from:

a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group;

a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group;

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group; and

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group,

xb1 may be selected from 0, 1, 2, and 3, and

xb2 may be selected from 1, 2, 3, and 4.

In some embodiments, in Formula 301,

L₃₀₁ may be selected from:

a phenylene group, a naphthylene group, a fluorenylene group, a spiro-fluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenanthrenylene group, an anthracenylene group, a pyrenylene group, and a chrysenylene group; and

a phenylene group, a naphthylene group, a fluorenylene group, a spiro-fluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenanthrenylene group, an anthracenylene group, a pyrenylene group, and a chrysenylene group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, and a chrysenyl group,

R₃₀₁ may be selected from:

a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group;

a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, and a chrysenyl group;

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, and a chrysenyl group; and

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, and a chrysenyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, and a chrysenyl group, but embodiments are not limited thereto.

In some embodiments, the host may include a compound represented by Formula 301A:

The descriptions of substituents in Formula 301A may be understood by referring to the descriptions thereof provided herein.

The compound represented by Formula 301 may include at least one compound selected from Compounds H1 to H42, but embodiments of the present disclosure are not limited thereto:

In some embodiments, the host may include at least one selected from Compounds H43 to H49, but embodiments are not limited thereto:

In some embodiments, the host may include at least one selected from compounds below, but embodiments are not limited thereto:

The dopant may be a phosphorescent dopant.

The phosphorescent dopant may include an organometallic complex represented by Formula 401:

In Formula 401,

M may be selected from iridium (Ir), platinum (Pt), osmium (Os), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu), terbium (Tb), and thulium (Tm);

X₄₀₁ to X₄₀₄ may be each independently nitrogen or carbon;

A₄₀₁ and A₄₀₂ rings may be each independently selected from a substituted or unsubstituted benzene, a substituted or unsubstituted naphthalene, a substituted or unsubstituted fluorene, a substituted or unsubstituted spiro-fluorene, a substituted or unsubstituted indene, a substituted or unsubstituted pyrrole, a substituted or unsubstituted thiophene, a substituted or unsubstituted furan, a substituted or unsubstituted imidazole, a substituted or unsubstituted pyrazole, a substituted or unsubstituted thiazole, a substituted or unsubstituted isothiazole, a substituted or unsubstituted oxazole, a substituted or unsubstituted isoxazole, a substituted or unsubstituted pyridine, a substituted or unsubstituted pyrazine, a substituted or unsubstituted pyrimidine, a substituted or unsubstituted pyridazine, a substituted or unsubstituted quinoline, a substituted or unsubstituted isoquinoline, a substituted or unsubstituted benzoquinoline, a substituted or unsubstituted quinoxaline, a substituted or unsubstituted quinazoline, a substituted or unsubstituted carbazole, a substituted or unsubstituted benzoimidazole, a substituted or unsubstituted benzofuran, a substituted or unsubstituted benzothiophene, a substituted or unsubstituted isobenzothiophene, a substituted or unsubstituted benzoxazole, a substituted or unsubstituted isobenzoxazole, a substituted or unsubstituted triazole, a substituted or unsubstituted oxadiazole, a substituted or unsubstituted triazine, a substituted or unsubstituted dibenzofuran, and a substituted or unsubstituted dibenzothiophene,

at least one substituent of the substituted benzene, substituted naphthalene, substituted fluorene, substituted spiro-fluorene, substituted indene, substituted pyrrole, substituted thiophene, substituted furan, substituted imidazole, substituted pyrazole, substituted thiazole, substituted isothiazole, substituted oxazole, substituted isoxazole, substituted pyridine, substituted pyrazine, substituted pyrimidine, substituted pyridazine, substituted quinoline, substituted isoquinoline, substituted benzoquinoline, substituted quinoxaline, substituted quinazoline, substituted carbazole, substituted benzoimidazole, substituted benzofuran, substituted benzothiophene, substituted isobenzothiophene, substituted benzoxazole, substituted isobenzoxazole, substituted triazole, substituted oxadiazole, substituted triazine, substituted dibenzofuran, and substituted dibenzothiophene may be selected from:

deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an am idino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q₄₀₁)(Q₄₀₂), —Si(Q₄₀₃)(Q₄₀₄)(Q₄₀₅), and —B(Q₄₀₆)(Q₄₀₇);

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q₄₁₁)(Q₄₁₂), —Si(Q₄₁₃)(Q₄₁₄)(Q₄₁₅), and —B(Q₄₁₆)(Q₄₁₇); and

—N(Q₄₂₁)(Q₄₂₂), —Si(Q₄₂₃)(Q₄₂₄)(Q₄₂₅), and —B(Q₄₂₆)(Q₄₂₇);

where Q₄₀₁ to Q₄₀₇, Q₄₁₁ to Q₄₁₇, and Q₄₂₁ to Q₄₂₇ may be each independently selected from hydrogen, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₆-C₆₀ aryl group, and a C₁-C₆₀ heteroaryl group;

L₄₀₁ may be an organic ligand;

xc1 may be selected from 1, 2, and 3; and

xc2 may be selected from 0, 1, 2, and 3.

In Formula 401, L₄₀₁ may be any suitable monovalent, divalent, or trivalent organic ligand. For example, L₄₀₁ may be selected from a halogen ligand (e.g., Cl and/or F), a diketone ligand (e.g., acetylacetonate, 1,3-diphenyl-1,3-propanedionate, 2,2,6,6-tetramethyl-3,5-heptanedionate, and/or hexafluoroacetonate), a carboxylic acid ligand (e.g., picolinate, dimethyl-3-pyrazolecarboxylate, and/or benzoate), a carbon monoxide ligand, an isonitrile ligand, a cyano ligand, and a phosphorous ligand (e.g., phosphine and/or phosphite), but embodiments are not limited thereto.

When A₄₀₁ in Formula 401 includes a plurality of substituents, the plurality of substituents of A₄₀₁ may be bound to each other to form a saturated or unsaturated ring.

When A₄₀₂ in Formula 401 includes a plurality of substituents, the plurality of substituents of A₄₀₂ may be bound to each other to form a saturated or unsaturated ring.

When xc1 in Formula 401 is 2 or more, a plurality of ligands

in Formula 401 may be identical to or different from each other. In Formula 401, when xc1 is 2 or more, A₄₀₁ and A₄₀₂ of one ligand may be each independently connected (e.g., coupled) to A₄₀₁ and A₄₀₂ of another adjacent ligand, respectively, either directly (e.g., via a bond such as a single bond) or via a linking group (e.g., a C₁-C₅ alkylene group, —N(R′)— (where R′ is a C₁-C₁₀ alkyl group or a C₆-C₂₀ aryl group), and/or —C(═O)—).

The phosphorescent dopant may include, for example, at least one selected from Compounds PD1 to PD21 and PD76, but embodiments are not limited thereto:

In some embodiments, the second layer 150 may be an emission layer. When the emission layer includes the second compound and the dopant, the amount of the dopant may be in a range of about 0.01 parts by weight to about 15 parts by weight, based on 100 parts by weight of the second compound, but embodiments are not limited thereto.

In some embodiments, the second layer 150 may be an emission layer. When the emission layer includes the second compound and the host, the amount of the second compound may be in a range of about 0.01 parts by weight to about 15 parts by weight, based on 100 parts by weight of the host, but embodiments are not limited thereto.

In some embodiments, the third layer 170 may be an emission layer. When the emission layer includes the third compound and the host, the amount of the third compound may be in a range of about 0.01 parts by weight to about 15 parts by weight, based on 100 parts by weight of the host, but embodiments are not limited thereto.

In some embodiments, the third layer 170 may be an emission layer. When the emission layer includes the third compound and the dopant, the amount of the dopant may be in a range of about 0.01 parts by weight to about 15 parts by weight, based on 100 parts by weight of the dopant, but embodiments are not limited thereto.

The thickness of the emission layer may be in a range of about 100 Å to about 1000 Å, for example, about 200 Å to about 600 Å. When the thickness of the emission layer is within any of these ranges, excellent (or suitable) light-emission characteristics may be achieved without a substantial increase in driving voltage.

Although not illustrated in the drawing, when the second layer 150 is an emission layer, an electron injection layer that facilitates electron injection may be additionally disposed (e.g., positioned) between the second electrode 190 and the third layer 170. The electron injection layer may be formed on the third layer 170 by using one or more suitable methods, such as vacuum deposition, spin coating, casting, an LB method, ink-jet printing, laser printing, and/or LITI. When the electron injection layer is formed by vacuum deposition and/or spin coating, the vacuum deposition and coating conditions for the electron injection layer may be similar to the vacuum deposition and coating conditions for the hole injection layer.

The electron injection layer may include at least one selected from LiF, NaCl, CsF, Li₂O, BaO, and LiQ.

The thickness of the electron injection layer may be in a range of about 1 Å to about 100 Å, for example, about 3 Å to about 90 Å. When the thickness of the electron injection layer is within any of these ranges, excellent (or suitable) electron injection characteristics may be obtained without a substantial increase in driving voltage.

In some embodiments, when the third layer 170 is an emission layer, at least one selected from an electron transport layer and an electron injection layer may be additionally disposed between the third layer 170 and the second electrode 190. The electron injection layer may be understood by referring to the description thereof provided herein.

The electron transport layer may include at least one selected from BCP, Bphen, Alq₃, BAlq, TAZ, and NTAZ:

The thickness of the electron transport layer may be in a range of about 100 Å to about 1000 Å, for example, about 150 Å to about 500 Å. When the thickness of the electron transport layer is within any of these ranges, excellent (or suitable) electron transport characteristics may be obtained without a substantial increase in driving voltage.

In some embodiments, the second layer 150 may be an emission layer, and the third layer 170 may be an electron transport layer.

The electron transport layer may further include a metal-containing material, in addition to the materials described above.

The metal-containing material may include a Li complex. The Li complex may include, for example, Compound ET-D1 (8-hydroxyquinolinolato-lithium or LiQ) and/or Compound ET-D2:

The second electrode 190 may be a cathode, that is an electron injection electrode. In this regard, a material for forming the second electrode 190 may be a material having a low work function, for example, a metal, an alloy, an electrically conductive compound, or a mixture thereof. Non-limiting examples of the material for forming the second electrode 190 may include lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), and magnesium-silver (Mg—Ag). In some embodiments, the material for forming the second electrode 190 may be ITO and/or IZO. The second electrode 190 may be a semi-transmissive electrode or a transmissive electrode.

A C₁-C₆₀ alkyl group used herein may refer to a linear or branched aliphatic hydrocarbon monovalent group having 1 to 60 carbon atoms. Non-limiting examples thereof include a methyl group, an ethyl group, a propyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an iso-amyl group, and a hexyl group. A C₁-C₆₀ alkylene group used herein may refer to a divalent group having the same structure as the C₁-C₆₀ alkyl group.

A C₁-C₆₀ alkoxy group used herein may refer to a monovalent group represented by —OA₁₀₁ (where A₁₀₁ is the C₁-C₆₀ alkyl group). Non-limiting examples thereof may include a methoxy group, an ethoxy group, and an isopropoxy group.

A C₂-C₆₀ alkenyl group used herein may refer to a hydrocarbon group having at least one carbon-carbon double bond at one or more positions along the hydrocarbon chain of the C₂-C₆₀ alkyl group (e.g., in the middle or at either terminal end of the C₂-C₆₀ alkyl group). Non-limiting examples thereof may include an ethenyl group, a propenyl group, and a butenyl group. A C₂-C₆₀ alkenylene group used herein may refer to a divalent group having the same structure as the C₂-C₆₀ alkenyl group.

A C₂-C₆₀ alkynyl group used herein may refer to a hydrocarbon group having at least one carbon-carbon triple bond at one or more positions along the hydrocarbon chain of the C₂-C₆₀ alkyl group (e.g., in the middle or at either terminal end of the C₂-C₆₀ alkyl group). Non-limiting examples thereof may include an ethynyl group and a propynyl group. A C₂-C₆₀ alkynylene group used herein may refer to a divalent group having the same structure as the C₂-C₆₀ alkynyl group.

A C₃-C₁₀ cycloalkyl group used herein may refer to a monovalent monocyclic saturated hydrocarbon group including 3 to 10 carbon atoms. Non-limiting examples thereof may include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group. A C₃-C₁₀ cycloalkylene group used herein may refer to a divalent group having the same structure as the C₃-C₁₀ cycloalkyl group.

A C₁-C₁₀ heterocycloalkyl group used herein may refer to a monovalent monocyclic group including at least one heteroatom selected from N, O, P, and S as a ring-forming atom, and 1 to 10 carbon atoms. Non-limiting examples thereof may include a tetrahydrofuranyl group and a tetrahydrothienyl group. A C₁-C₁₀ heterocycloalkylene group used herein may refer to a divalent group having the same structure as the C₁-C₁₀ heterocycloalkyl group.

A C₃-C₁₀ cycloalkenyl group as used herein may refer to a monovalent monocyclic group that has 3 to 10 carbon atoms and at least one double bond in its ring, and is not aromatic. Non-limiting examples thereof may include a cyclopentenyl group, a cyclohexenyl group, and a cycloheptenyl group. A C₃-C₁₀ cycloalkenylene group used herein may refer to a divalent group having the same structure as the C₃-C₁₀ cycloalkenyl group.

A C₁-C₁₀ heterocycloalkenyl group used herein may refer to a monovalent monocyclic group including at least one heteroatom selected from N, O, P, and S as a ring-forming atom, 1 to 10 carbon atoms, and at least one double bond in its ring. Non-limiting examples of the C₁-C₁₀ heterocycloalkenyl group may include a 2,3-dihydrofuranyl group and a 2,3-dihydrothienyl group. A C₁-C₁₀ heterocycloalkenylene group used herein may refer to a divalent group having the same structure as the C₁-C₁₀ heterocycloalkenyl group.

A C₆-C₆₀ aryl group used herein may refer to a monovalent group including a carbocyclic aromatic system having 6 to 60 carbon atoms. A C₆-C₆₀ arylene group used herein may refer to a divalent group including a carbocyclic aromatic system having 6 to 60 carbon atoms.

A C₆-C₆₀ non-condensed arylene group used herein may refer to a divalent group including a carbocyclic aromatic system having 6 to 60 carbon atoms, and not including two or more rings. A C₆-C₆₀ condensed polycyclic arylene group used herein may refer to a divalent group including a carbocyclic aromatic system having 6 to 60 carbon atoms, and including two or more rings.

Non-limiting examples of the C₆-C₆₀ aryl group may include a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, and a chrysenyl group.

A non-limiting example of the C₆-C₆₀ non-condensed arylene group may include a phenylene group. Non-limiting examples of the C₆-C₆₀ condensed polycyclic arylene group may include a naphthylene group, an anthracenylene group, a phenanthrenylene group, a pyrenylene group, and a chrysenylene group.

When the C₆-C₆₀ aryl group and the C₆-C₆₀ arylene group each independently include a plurality of rings, the respective rings may be fused to each other.

A C₁-C₆₀ heteroaryl group used herein may refer to a monovalent group having a carbocyclic aromatic system including at least one heteroatom selected from N, O, P, and S as a ring-forming atom, and 1 to 60 carbon atoms. A C₁-C₆₀ heteroarylene group used herein may refer to a divalent group having a carbocyclic aromatic system including at least one heteroatom selected from N, O, P, and S as a ring-forming atom, and 1 to 60 carbon atoms.

A C₁-C₆₀ non-condensed heteroarylene group used herein may refer to a divalent group having a carbocyclic aromatic system including at least one heteroatom selected from N, O, P, and S as a ring-forming atom, and 1 to 60 carbon atoms, and not including two or more rings. A C₁-C₆₀ condensed polycyclic heteroarylene group used herein may refer to a divalent group having a carbocyclic aromatic system including at least one heteroatom selected from N, O, P, and S as a ring-forming atom, and 1 to 60 carbon atoms, and including two or more rings.

Non-limiting examples of the C₁-C₆₀ heteroaryl group may include a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, and an isoquinolinyl group.

Non-limiting examples of the C₁-C₆₀ non-condensed heteroarylene group may include a pyridinylene group, a pyrimidinylene group, a pyrazinylene group, a pyridazinylene group, and a triazinylene group. Non-limiting examples of the C₁-C₆₀ condensed polycyclic heteroarylene group may include a quinolinylene group, an isoquinolinylene group, a quinoxalinylene group, and a phthalazinylene group. When the C₁-C₆₀ heteroaryl group and the C₁-C₆₀ heteroarylene group each independently include a plurality of rings, the respective rings may be fused to each other.

A C₆-C₆₀ aryloxy group used herein may refer to a group represented by —OA₁₀₂ (where A₁₀₂ is the C₆-C₆₀ aryl group). A C₆-C₆₀ arylthio group used herein may refer to a group represented by -SA₁₀₃ (where A₁₀₃ is the C₆-C₆₀ aryl group).

A monovalent non-aromatic condensed polycyclic group used herein may refer to a monovalent group that has two or more rings condensed to each other, has only carbon atoms as ring-forming atoms (for example, the number of carbon atoms may be in a range of 8 to 60), and does not have overall aromaticity in the entire molecular structure. A non-limiting example of the monovalent non-aromatic condensed polycyclic group may include a fluorenyl group. A divalent non-aromatic condensed polycyclic group used herein may refer to a divalent group having the same structure as the monovalent non-aromatic condensed polycyclic group.

A monovalent non-aromatic condensed heteropolycyclic group used herein may refer to a monovalent group that has two or more rings condensed to each other, has at least one heteroatom selected from N, O, P, and S as a ring-forming atom, other than carbon atoms (for example, the number of carbon atoms may be in a range of 2 to 60), and does not have overall aromaticity in the entire molecular structure. Non-limiting example of the monovalent non-aromatic condensed heteropolycyclic group includes a carbazolyl group. A divalent non-aromatic condensed heteropolycyclic group used herein may refer to a divalent group having the same structure as the monovalent non-aromatic condensed heteropolycyclic group.

In the present specification, at least one substituent of the substituted C₃-C₁₀ cycloalkylene group, substituted C₁-C₁₀ heterocycloalkylene group, substituted C₃-C₁₀ cycloalkenylene group, substituted C₁-C₁₀ heterocycloalkenylene group, substituted C₆-C₆₀ arylene group, substituted C₆-C₆₀ non-condensed arylene group, substituted C₆-C₆₀ condensed polycyclic arylene group, substituted C₁-C₆₀ heteroarylene group, substituted C₁-C₆₀ non-condensed heteroarylene group, substituted C₁-C₆₀ condensed polycyclic heteroarylene group, substituted divalent non-aromatic condensed polycyclic group, substituted divalent non-aromatic condensed heteropolycyclic group, substituted C₁-C₆₀ alkyl group, substituted C₂-C₆₀ alkenyl group, substituted C₂-C₆₀ alkynyl group, substituted C₁-C₆₀ alkoxy group, substituted C₃-C₁₀ cycloalkyl group, substituted C₁-C₁₀ heterocycloalkyl group, substituted C₃-C₁₀ cycloalkenyl group, substituted C₁-C₁₀ heterocycloalkenyl group, substituted C₆-C₆₀ aryl group, substituted C₆-C₆₀ aryloxy group, substituted C₆-C₆₀ arylthio group, substituted C₁-C₆₀ heteroaryl group, substituted monovalent non-aromatic condensed polycyclic group, and substituted monovalent non-aromatic condensed heteropolycyclic group may be selected from:

deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, and —Si(Q₁₃)(Q₁₄)(Q₁₅),

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group, and —Si(Q₂₃)(Q₂₄)(Q₂₅); and

—Si(Q₃₃)(Q₃₄)(Q₃₅),

wherein Q₁₃ to Q₁₅, Q₂₃ to Q₂₅, and Q₃₃ to Q₃₅ may be each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group.

In some embodiments, at least one substituent of the substituted C₃-C₁₀ cycloalkylene group, substituted C₁-C₁₀ heterocycloalkylene group, substituted C₃-C₁₀ cycloalkenylene group, substituted C₁-C₁₀ heterocycloalkenylene group, substituted C₆-C₆₀ arylene group, substituted C₆-C₆₀ non-condensed arylene group, substituted C₆-C₆₀ condensed polycyclic arylene group, substituted C₁-C₆₀ heteroarylene group, substituted C₁-C₆₀ non-condensed heteroarylene group, substituted C₁-C₆₀ condensed polycyclic heteroarylene group, substituted divalent non-aromatic condensed polycyclic group, substituted divalent non-aromatic condensed heteropolycyclic group, substituted C₁-C₆₀ alkyl group, substituted C₂-C₆₀ alkenyl group, substituted C₂-C₆₀ alkynyl group, substituted C₁-C₆₀ alkoxy group, substituted C₃-C₁₀ cycloalkyl group, substituted C₁-C₁₀ heterocycloalkyl group, substituted C₃-C₁₀ cycloalkenyl group, substituted C₁-C₁₀ heterocycloalkenyl group, substituted C₆-C₆₀ aryl group, substituted C₆-C₆₀ aryloxy group, substituted C₆-C₆₀ arylthio group, substituted C₁-C₆₀ heteroaryl group, substituted monovalent non-aromatic condensed polycyclic group, and substituted monovalent non-aromatic condensed heteropolycyclic group may be selected from:

deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group, a thienyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, a benzofuranyl group, a benzothienyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothienyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, and —Si(Q₁₃)(Q₁₄)(Q₁₅);

a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group, a thienyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, a benzofuranyl group, a benzothienyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothienyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group;

a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group, a thienyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, a benzofuranyl group, a benzothienyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothienyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group, a thienyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, a benzofuranyl group, a benzothienyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothienyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, and —Si(Q₂₃)(Q₂₄)(Q₂₅); and

—Si(Q₃₃)(Q₃₄)(Q₃₅),

wherein Q₁₃ to Q₁₅, Q₂₃ to Q₂₅, and Q₃₃ to Q₃₅ may be each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group, a thienyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoimidazolyl group, a benzofuranyl group, a benzothienyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothienyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group.

“Ph” used herein may refer to a phenyl group, “Me” may refer to a methyl group, “Et” may refer to an ethyl group, and “ter-Bu” or “Bu^(t)” may refer to a tert-butyl group.

“A biphenyl group” may refer to a monovalent group in which two benzene rings are bound (e.g., coupled) to each other via a single bond. “A terphenyl group” may refer to a monovalent group in which three benzene rings are bound (e.g., coupled) via single bonds.

Hereinafter an organic light-emitting device according to an embodiment will be described in detail with reference to Examples and Synthesis Examples below. The expression “‘B’ was used instead of ‘A’” used in describing Synthesis Examples below means that the number of molar equivalents of ‘B’ used was identical to the number of molar equivalents of ‘A’”.

EXAMPLES Synthesis Examples Synthesis Example 1: Synthesis of Compound 1-3

Synthesis of Intermediate 1-3

0.04 mol of Intermediate 1-1, 0.04 mol of Intermediate 1-2, 2 mmol of tetrakis(triphenylphosphine)palladium, 20 ml of 2M K₂CO₃ aqueous solution, 20 ml of ethanol, and 50 ml of toluene were mixed together, and then, the mixed solution was stirred for 4 hours while being heated at a temperature of about 120° C. After completion of the reaction, an extraction process was performed thereon using ethyl acetate and distilled water. An organic layer collected therefrom was dried using anhydrous magnesium sulfate, and then, filtered. The filtrate was concentrated under reduced pressure, and the resulting product was purified by column chromatography, thereby completing the preparation of Intermediate 1-3.

Synthesis of Intermediate 1-4

0.03 mol of Intermediate 1-3 was dissolved in 100 ml of TFT, and then, the mixed solution was cooled down to a temperature of −78° C. 0.07 mol of 2.5M n-butyl lithium was added thereto, and after one hour, 0.07 mol of isopropyl borate was added to the reaction solution. The resulting reaction solution was then stirred under reflux for 17 hours. After completion of the reaction, an extraction process was performed thereon using ethyl acetate and distilled water. An organic layer collected therefrom was dried using anhydrous magnesium sulfate, and then, filtered. The filtrate was concentrated under reduced pressure, thereby completing the preparation of Intermediate 1-4.

Synthesis of Compound 1-3

0.02 mol of Intermediate 1-4, 0.03 mol of 4-bromo-dibenzo[b,d]furan, 1 mmol of Pd(PPh₃)₄, 0.04 mol of K₂CO₃ aqueous solution, 100 ml of toluene, 25 ml of EtOH, and 25 ml of H₂O were mixed together, and then, the mixed solution was stirred under reflux for 13 hours. After completion of the reaction, an extraction process was performed thereon using dichloromethane and distilled water. An organic layer collected therefrom was dried using anhydrous magnesium sulfate, and then, filtered. The filtrate was concentrated under reduced pressure, and the resulting product was purified by column chromatography, thereby completing the preparation of Compound 1-3.

T₁ (triplet energy of Compound 1-3)=2.2 eV

Synthesis Example 2: Synthesis of Compound 2-8

Synthesis of Compound 2-8

0.02 mol of Intermediate 2-1 and 0.02 mol of Intermediate 2-2, 0.06 mol of sodium t-butoxide, and 1 mmol of tri-tert-butylphosphine were dissolved in 100 ml of toluene, and then, 1 mmol of Pd(dba)₂ was added thereto. Then, the mixed solution was stirred under reflux for 12 hours in a nitrogen atmosphere. After completion of the reaction, an extraction process was performed thereon using toluene and distilled water. An organic layer collected therefrom was dried using anhydrous magnesium sulfate, and then filtered. The filtrate was concentrated under reduced pressure. The resulting product was purified by column chromatography using normal hexane/dichloromethane (at a volume ratio of 2:1), thereby completing the preparation of Compound 2-8.

T₁ (triplet energy of Compound 2-8)=2.6 eV

Synthesis Example 3: Compound 3-1

Synthesis of Compound 3-1

0.05 mol of Intermediate 3-1, 0.02 mol of Intermediate 3-2, 0.8 mol of sodium t-butoxide, and 1 mmol of tri-tert-butylphosphine were dissolved in 100 ml of toluene, and 2 mmol of Pd(dba)₂ was added thereto. Then, the mixed solution was stirred under reflux for 12 hours in a nitrogen atmosphere. After completion of the reaction, an extraction process was performed thereon using toluene and distilled water. An organic layer collected therefrom was dried using anhydrous magnesium sulfate, and then, filtered. The resulting product was purified by column chromatography, thereby completing the preparation of Compound 3-1.

T₁ (triplet energy of Compound 3-1)=2.0 eV

Synthesis Example 4: Synthesis of Compound 4-5

Synthesis of Intermediate 4-1

0.02 mol of 1-bromo-2-nitrobenzene, 0.022 mol of dibenzo[b,d]furan-3-ylboronic acid, 1 mmol of tetrakis(triphenylphosphine)palladium, 30 ml of 2M K₂CO₃ aqueous solution, 30 ml of ethanol, and 60 ml of toluene were mixed together, and then, the mixed solution was stirred for 4 hours while being heated at a temperature of 120° C. After completion of the reaction, an extraction process was performed thereon using ethyl acetate and distilled water. An organic layer collected therefrom was dried using anhydrous magnesium sulfate, and then, filtered. The filtrate was concentrated under reduced pressure, and the resulting product was purified by column chromatography, thereby completing the preparation of Intermediate 4-1.

Synthesis of Intermediate 4-2

0.02 mol Intermediate 4-1, 60 ml of triethylphosphite, and 30 ml of 1,2-dichlorobenzene were mixed together, and then, the mixed solution was stirred for 12 hours while being heated at a temperature of 150° C. After completion of the reaction, a distillation apparatus was used thereon to remove unreacted triethylphosphite and unreacted 1,2-dichlorobenzene, and an extraction process was performed thereon using ethyl acetate and distilled water. An organic layer collected therefrom was dried using anhydrous magnesium sulfate, and then, filtered. The filtrate was concentrated under reduced pressure, and the resulting product was purified by column chromatography, thereby completing the preparation of Intermediate 4-2.

Synthesis of Compound 4-5

4 mmol of NaH solution was dissolved in dimethylformamide, and then, the mixed solution was stirred. After 3 mmol of Intermediate 4-2 was dissolved in separate dimethylformamide, the resulting solution was added to the NaH to be stirred. The mixed solution was stirred for 1 hour, and then, mixed with a solution in which 3.5 mmol of 2-(3-bromophenyl)-4,6-diphenyl-1,3,5-triazine was dissolved and stirred for 1 hour in DMF. Then, the reaction solution was stirred for 24 hours at room temperature. After completion of the reaction, the resulting solid product was filtered, washed using ethyl acetate, and then, purified by column chromatography, thereby completing the preparation of Compound 4-5.

T₁ (triplet energy of Compound 4-5)=2.5 eV

Synthesis Example 5: Synthesis of Compound 5-3

Synthesis of Intermediate 5-1

0.04 mol of dibenzofuran-4-ylboronic acid, 0.05 mol of 1-bromo-3-iodobenzene, 2 mmol of Pd(PPh₃)₄, 0.08 mol K₂CO₃ aqueous solution, 100 ml of toluene, 25 ml of EtOH, and 25 ml of H₂O were mixed together in a 250 ml round-bottomed flask, and then, the mixed solution was stirred under reflux for 4 hours. After completion of the reaction, an extraction process was performed thereon using dichloromethane and distilled water. An organic layer collected therefrom was dried using anhydrous magnesium sulfate, and then filtered. The resulting product was purified by column chromatography, thereby completing the preparation of Intermediate 5-1.

Synthesis of Intermediate 5-2

0.03 mol of Intermediate 5-1 was added to a 500 ml round-bottomed flask, and then, 100 ml of THF was added thereto. The mixed solution was cooled down to a temperature −78° C. 0.05 mol of 2.5M n-butyl lithium was added to the resulting solution, and after one hour, 0.05 mol of isopropyl borate was added thereto. The reaction solution was then stirred under reflux for 17 hours. After completion of the reaction, an extraction process was performed thereon using ethyl acetate and distilled water. An organic layer collected therefrom was dried using anhydrous magnesium sulfate, and then, filtered. The filtrate was concentrated under reduced pressure, thereby completing the preparation of Intermediate 5-2.

Synthesis of Intermediate 5-3

0.02 mol of Intermediate 5-2, 0.03 mol of 1-phenyl-3,5-dichloropyridine, 1 mmol of Pd(PPh₃)₄, 0.04 mol of K₂CO₃ aqueous solution, 100 mol of toluene, 25 ml of EtOH, and 25 ml of H₂O were mixed together in a 1 L round-bottomed flask, and then, the mixed solution was stirred under reflux for 13 hours. After completion of the reaction, an extraction process was performed thereon using dichloromethane and distilled water. An organic layer collected therefrom was dried using anhydrous magnesium sulfate, and then, filtered. The resulting product was purified by column chromatography, thereby completing the preparation of Intermediate 5-3.

Synthesis of Compound 5-3

0.01 mol of Intermediate 5-3, 0.012 mol of (3-(9-carbazole-9-yl)phenyl)boronic acid, 0.015 mol of NaH, and 150 ml of dimethylformamide were mixed together, and then, the mixed solution was stirred for 5 hours at room temperature. After completion of the reaction, an extraction process was performed thereon using ethyl acetate and distilled water. Then, an organic layer collected therefrom was dried using anhydrous magnesium sulfate, and filtered to remove the solvent. The resulting product was purified by column chromatography, thereby completing the preparation of Compound 5-3.

T₁ (triplet energy of Compound 5-3)=2.6 eV

Example 1-1

An indium tin oxide (ITO) glass substrate (available from Corning Inc.) with an ITO layer having a thickness of 15 Ω/cm² (1,200 Å) thereon was cut to a size of 50 mm×50 mm×0.5 mm, sonicated by using isopropyl alcohol and pure water each for 15 minutes, and cleaned by exposure to ultraviolet rays for 30 minutes and then ozone, and the resulting ITO glass anode was mounted on a vacuum deposition apparatus.

On the ITO glass anode, Compound 1-9 was vacuum-deposited to form a hole transport layer (e.g., first layer) having a thickness of about 1,200 Å. Compound 4-5 (as a host) and PD17 (as a dopant) were next co-deposited on the hole transport layer at a weight ratio of about 95:5 to form an emission layer (e.g., second layer) having a thickness of about 300 Å.

Compound 5-3 was then vacuum-deposited on the emission layer to form a first electron transport layer (e.g., third layer) having a thickness of about 100 Å, followed by vacuum deposition of BAlq on the first electron transport layer to form a second electron transport layer having a thickness of about 300 Å. LiF was vacuum-deposited on the second electron transport layer to form an electron injection layer having a thickness of about 10 Å.

Thereafter, Al was vacuum-deposited on the electron injection layer to form a cathode having a thickness of about 2,000 Å, thereby completing the manufacture of an organic light-emitting device.

Examples 1-2 to 1-5

Organic light-emitting devices were manufactured in the same (or substantially the same) manner as in Example 1-1, except that materials as shown in Table 1 were used.

Comparative Example 1-1

An organic light-emitting device was manufactured in the same (or substantially the same) manner as in Example 1-1, except that CBP was used instead of Compound 4-5 in forming the emission layer.

Comparative Example 1-2

An organic light-emitting device was manufactured in the same (or substantially the same) manner as in Example 1-1, except that a first electron transport layer was not formed, and BAlq was vacuum-deposited on the emission layer to form an electron transport layer having a thickness of about 400 Å.

Example 2-1

An ITO glass substrate (available from Corning Inc.) with an ITO layer having a thickness of 15 Ω/cm² (1,200 Å) thereon was cut to a size of 50 mm×50 mm×0.5 mm, sonicated by using isopropyl alcohol and pure water each for 15 minutes, and cleaned by exposure to ultraviolet rays for 30 minutes and then ozone, and the resulting ITO glass anode was mounted on a vacuum deposition apparatus.

On the ITO glass anode, Compound 1-9 was vacuum-deposited to form a first hole transport layer (e.g., first layer) having a thickness of about 1,100 Å. Compound 2-8 was next vacuum-deposited on the first hole transport layer to form a second hole transport layer (e.g., second layer) having a thickness of about 100 Å. Compound 4-5 (as a host) and PD17 (as a dopant) were next co-deposited on the second hole transport layer at a weight ratio of about 95:5 to form an emission layer (e.g., third layer) having a thickness of about 300 Å.

Thereafter, BAlq was vacuum-deposited on the emission layer to form an electron transport layer having a thickness of 400 Å. LiF was vacuum-deposited on the electron transport layer to form an electron injection layer having a thickness of about 10 Å, and Al was vacuum-deposited on the electron injection layer to form a cathode having a thickness of about 2,000 Å, thereby completing the manufacture of an organic light-emitting device.

Examples 2-2 to 2-5

Organic light-emitting devices were manufactured in the same (or substantially the same) manner as in Example 2-1, except that materials as shown in Table 2 were used.

Comparative Example 2-1

An organic light-emitting device was manufactured in the same (or substantially the same) manner as in Example 2-1, except that CBP was used instead of Compound 4-5 in forming the emission layer.

Comparative Example 2-2

An organic light-emitting device was manufactured in the same (or substantially the same) manner as in Example 2-1, except that compound HT3 was used instead of Compound 2-8 in forming the second hole transport layer.

Comparative Example 2-3

An organic light-emitting device was manufactured in the same (or substantially the same) manner as in Example 2-1, except that NPB was used instead of Compound 1-9 in forming the first hole transport layer, and Compound 2-4 was used instead of Compound 2-8 in forming the second hole transport layer.

Example 3-1

An ITO glass substrate (available from Corning Inc.) with an ITO layer having a thickness of 15 Ω/cm² (1,200 Å) thereon was cut to a size of 50 mm×50 mm×0.5 mm, sonicated by using isopropyl alcohol and pure water each for 15 minutes, and cleaned by exposure to ultraviolet rays for 30 minutes and then ozone, and the resulting ITO glass anode was mounted on a vacuum deposition apparatus.

On the ITO glass anode, Compound 1-9 was vacuum-deposited to form a hole transport layer (e.g., first layer) having a thickness of about 1,200 Å. Compound ADN (as a host) and Compound 3-1 (as a dopant) were next co-deposited on the hole transport layer at a weight ratio of about 95:5 to form an emission layer (e.g., second layer) having a thickness of about 300 Å.

Compound 5-3 was then vacuum-deposited on the emission layer to form a first electron transport layer (e.g., third layer) having a thickness of about 100 Å, followed by vacuum deposition of Alq₃ on the first electron transport layer to form a second electron transport layer having a thickness of about 300 Å. LiF was vacuum-deposited on the second electron transport layer to form an electron injection layer having a thickness of about 10 Å.

Thereafter, Al was vacuum-deposited on the electron injection layer to form a cathode having a thickness of about 2,000 Å, thereby completing the manufacture of an organic light-emitting device.

Examples 3-2 to 3-5

Organic light-emitting devices were manufactured in the same (or substantially the same) manner as in Example 3-1, except that materials as shown in Table 3 were used.

Comparative Example 3-1

An organic light-emitting device was manufactured in the same (or substantially the same) manner as in Example 3-1, except that compound FD1 (illustrated below) was used instead of Compound 3-1 in forming the emission layer.

Comparative Example 3-2

An organic light-emitting device was manufactured in the same (or substantially the same) manner as in Example 3-1, except that a first electron transport layer was not formed, and Alq₃ was vacuum-deposited on the emission layer to form an electron transport layer having a thickness of about 400 Å.

Example 4-1

An ITO glass substrate (available from Corning Inc.) with an ITO layer having a thickness of 15 Ω/cm² (1,200 Å) thereon was cut to a size of 50 mm×50 mm×0.5 mm, sonicated by using isopropyl alcohol and pure water each for 15 minutes, and cleaned by exposure to ultraviolet rays for 30 minutes and then ozone, and the resulting ITO glass anode was mounted on a vacuum deposition apparatus.

On the ITO glass anode, Compound 1-9 was vacuum-deposited to form a first hole transport layer (e.g., first layer) having a thickness of about 1,100 Å. Compound 2-8 was next vacuum-deposited on the first hole transport layer to form a second hole transport layer (e.g., second layer) having a thickness of about 100 Å. Compound ADN (as a host) and Compound 3-1 (as a dopant) were next co-deposited on the second hole transport layer at a weight ratio of about 95:5 to form an emission layer (e.g., third layer) having a thickness of about 300 Å.

Thereafter, Alq₃ was vacuum-deposited on the emission layer to form an electron transport layer having a thickness of 400 Å. LiF was vacuum-deposited on the electron transport layer to form an electron injection layer having a thickness of about 10 Å, and Al was vacuum-deposited on the electron injection layer to form a cathode having a thickness of about 2,000 Å, thereby completing the manufacture of an organic light-emitting device.

Examples 4-2 to 4-5

Organic light-emitting devices were manufactured in the same (or substantially the same) manner as in Example 4-1, except that materials as shown in Table 4 were used.

Comparative Example 4-1

An organic light-emitting device was manufactured in the same (or substantially the same) manner as in Example 4-1, except that compound FD1 was used instead of Compound 3-1 in forming the emission layer.

Comparative Example 4-2

An organic light-emitting device was manufactured in the same (or substantially the same) manner as in Example 4-1, except that compound HT3 was used instead of Compound 2-8 in forming the second hole transport layer.

Evaluation Example 1

The efficiency and T90 lifespan of organic light-emitting devices manufactured in Examples 1-1 to 1-5, 2-1 to 2-5, 3-1 to 3-5, and 4-1 to 4-5 and Comparative Examples 1-1, 1-2, 2-1 to 2-3, 3-1, 3-2, 4-1, and 4-2 were measured using a luminance meter PR650 (PhotoResearch, Inc.). The results are shown in Tables 1 to 4. The T90 lifespan indicates a time that it took for the luminance of the organic light-emitting device to decline to 90% of its initial luminance, under a luminance condition of 150 nits.

TABLE 1 Hole First electron transport transport layer Host layer Efficiency Lifespan material material material (cd/A) (T90, hr) Example 1-1 1-9 4-5  5-3 22.1 126 Example 1-2 1-9 4-10 5-4 22.8 139 Example 1-3 1-3 4-5  5-3 21.7 151 Example 1-4 1-3 4-11 5-8 20.9 140 Example 1-5 1-7 4-11 5-6 22.5 163 Comparative 1-9 CBP 5-3 16.2 58 Example 1-1 Comparative 1-9 4-5  — 12.7 65 Example 1-2

TABLE 2 Second First hole hole transport transport layer layer Host Efficiency Lifespan material material material (cd/A) (T90, hr) Example 2-1 1-9 2-8 4-5 19.8 137 Example 2-2 1-9 2-5 5-2 21.5 148 Example 2-3 1-3 2-8 4-5 20.9 120 Example 2-4 1-3 2-5 5-9 19.5 131 Example 2-5 1-7 2-4 5-1 20.3 145 Comparative 1-9 2-8 CBP 16.4 73 Example 2-1 Comparative 1-9 HT3 4-5 15.2 78 Example 2-2 Comparative NPB 2-4 4-5 18.2 102 Example 2-3

TABLE 3 Hole First electron transport transport layer Dopant layer Efficiency Lifespan material material material (cd/A) (T90, hr) Example 3-1 1-9 3-1 5-3 5.8 55 Example 3-2 1-9 3-2 5-4 5.4 61 Example 3-3 1-3 3-1 5-3 5.3 51 Example 3-4 1-3 3-2 5-8 5.7 70 Example 3-5 1-7 3-1 5-6 5.9 82 Comparative 1-9 FD1 5-3 4.9 33 Example 3-1 Comparative 1-9 3-1 — 4.4 29 Example 3-2

TABLE 4 First hole Second hole transport transport layer layer Dopant Efficiency Lifespan material material material (cd/A) (T90, hr) Example 4-1 1-9 2-8 3-1 5.1 60 Example 4-2 1-9 2-5 3-2 5.3 75 Example 4-3 1-3 2-8 3-1 4.9 55 Example 4-4 1-3 2-5 3-2 5.3 83 Example 4-5 1-7 2-4 3-1 5.4 88 Comparative 1-9 2-8 FD1 4.3 21 Example 4-1 Comparative 1-9 HT3 3-1 4.5 27 Example 4-2

Referring to Tables 1 to 4, it was found that the organic light-emitting devices manufactured in Examples 1-1 to 1-5, 2-1 to 2-5, 3-1 to 3-5, and 4-1 to 4-5 had excellent efficiency and lifespan, as compared to the organic light-emitting devices manufactured in Comparative Examples 1-1, 1-2, 2-1 to 2-3, 3-1, 3-2, 4-1, and 4-2.

As described above, an organic light-emitting device according to embodiments of the present disclosure may have low-driving voltage, improved efficiency, and long lifespan.

As used herein, the terms “use,” “using,” and “used” may be considered synonymous with the terms “utilize,” “utilizing,” and “utilized,” respectively.

In addition, as used herein, the terms “substantially,” “about,” and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent deviations in measured or calculated values that would be recognized by those of ordinary skill in the art.

Also, any numerical range recited herein is intended to include all subranges of the same numerical precision subsumed within the recited range. For example, a range of “1.0 to 10.0” is intended to include all subranges between (and including) the recited minimum value of 1.0 and the recited maximum value of 10.0, that is, having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limitation recited herein is intended to include all lower numerical limitations subsumed therein and any minimum numerical limitation recited in this specification is intended to include all higher numerical limitations subsumed therein. Accordingly, Applicant reserves the right to amend this specification, including the claims, to expressly recite any sub-range subsumed within the ranges expressly recited herein.

It should be understood that example embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each example embodiment should typically be considered as available for other similar features or aspects in other example embodiments.

While one or more example embodiments have been described with reference to the drawing, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the following claims and equivalents thereof. 

What is claimed is:
 1. An organic light-emitting device comprising: a first electrode; a second electrode facing the first electrode; a first layer between the first electrode and the second electrode, the first layer comprising a first compound; a second layer between the first layer and the second electrode, the second layer comprising a second compound; and a third layer between the second layer and the second electrode, the third layer comprising a third compound; wherein the first compound does not comprise a nitrogen-containing heterocyclic group comprising *═N—*′ as a ring forming moiety, and wherein the first compound and the second compound each independently comprise at least one group selected from groups represented by Formulae A to C:

wherein, in Formulae A to C, ring A₁, ring A₁₁, and ring A₁₂ are each independently selected from a C₅-C₃₀ carbocyclic group and a C₂-C₃₀ heterocyclic group, R₁, R₂, R₁₁, and R₁₂ are each independently selected from: hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group; a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, and a phosphoric acid group or a salt thereof; a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group; a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group; and —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), and —B(Q₆)(Q₇), wherein Q₁ to Q₇ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, a1, a11, and a12 are each independently an integer selected from 0 to 10, a2 is an integer selected from 0 to 2, wherein * and *′ each indicate a binding site to an adjacent atom, and wherein the third compound selected from compounds represented by Formulae 3-1 and 3-2:

wherein, in Formulae 3-1, and 3-2, X₁ is C(R₄₁) or N, X₂ is C(R₄₂) or N, X₃ is C(R₄₃) or N, L₄₁ to L₄₃ are each independently selected from a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group, g1 to g3 are each independently an integer selected from 0 to 3, Ar₄₁ to Ar₄₃ are each independently a group selected from groups represented by Formulae A to C, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a biphenyl group, a terphenyl group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, R₄₁ to R₄₄ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an am idino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, and —Si(Q₄₃)(Q₄₄)(Q₄₅), h1, and h4 are each independently an integer selected from 0 to 4, and h2, and h3 are each independently an integer selected from 0 to 3, at least one substituent of the substituted C₃-C₁₀ cycloalkylene group, substituted C₁-C₁₀ heterocycloalkylene group, substituted C₃-C₁₀ cycloalkenylene group, substituted C₁-C₁₀ heterocycloalkenylene group, substituted C₆-C₆₀ arylene group, substituted C₆-C₆₀ non-condensed arylene group, substituted C₆-C₆₀ condensed polycyclic arylene group, substituted C₁-C₆₀ heteroarylene group, substituted C₁-C₆₀ non-condensed heteroarylene group, substituted C₁-C₆₀ condensed polycyclic heteroarylene group, substituted divalent non-aromatic condensed polycyclic group, substituted divalent non-aromatic condensed heteropolycyclic group, substituted C₁-C₆₀ alkyl group, substituted C₂-C₆₀ alkenyl group, substituted C₂-C₆₀ alkynyl group, substituted C₁-C₆₀ alkoxy group, substituted C₃-C₁₀ cycloalkyl group, substituted C₁-C₁₀ heterocycloalkyl group, substituted C₃-C₁₀ cycloalkenyl group, substituted C₁-C₁₀ heterocycloalkenyl group, substituted C₆-C₆₀ aryl group, substituted C₆-C₆₀ aryloxy group, substituted C₆-C₆₀ arylthio group, substituted C₁-C₆₀ heteroaryl group, substituted monovalent non-aromatic condensed polycyclic group, and substituted monovalent non-aromatic condensed heteropolycyclic group is selected from: deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group; a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, and —Si(Q₁₃)(Q₁₄)(Q₁₅); a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group; a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group, and —Si(Q₂₃)(Q₂₄)(Q₂₅); and —Si(Q₃₃)(Q₃₄)(Q₃₅), wherein Q₁, Q₂, Q₁₃ to Q₁₅, Q₂₃ to Q₂₅, Q₃₃ to Q₃₅, and Q₄₃ to Q₄₅ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group.
 2. The organic light-emitting device of claim 1, wherein at least two selected from the first compound, the second compound, and the third compound have a triplet energy of 2.4 eV or greater.
 3. The organic light-emitting device of claim 1, wherein each of the first compound, the second compound, and the third compound has an asymmetrical structure.
 4. The organic light-emitting device of claim 1, wherein ring A₁, ring A₁₁, and ring A₁₂ are each independently selected from a benzene group, a naphthalene group, a fluorene group, a benzofluorene group, a pyridine group, a pyrimidine group, a carbazole group, a benzocarbazole group, and a dibenzothiophene group.
 5. The organic light-emitting device of claim 1, wherein, in Formulae A to C, R₁, R₂, R₁₁, and R₁₂ are each independently selected from: hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group; a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, and a phosphoric acid group or a salt thereof; a phenyl group, a biphenyl group, a terphenyl group, a fluorenyl group, a naphthyl group, a pyridinyl group, a pyrimidinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a quinazolinyl group, and a quinoxalinyl group; a phenyl group, a biphenyl group, a terphenyl group, a fluorenyl group, a naphthyl group, a pyridinyl group, a pyrimidinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a quinazolinyl group, and a quinoxalinyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an am idino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, and a C₆-C₁₆ aryl group; and —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), and —B(Q₆)(Q₇), wherein Q₁ to Q₇ are each independently selected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a fluorenyl group, and a naphthyl group.
 6. The organic light-emitting device of claim 1, wherein the first compound, the second compound, and the third compound each independently comprise at least one group selected from groups represented by Formulae A(1), A(2), B(1) to B(4), and C(1) to C(16):

wherein, in Formulae A(1), A(2), B(1) to B(4), and C(1) to C(16), R_(1a) to R_(1d) are defined as R₁, R_(2a) and R_(2b) are defined as R₂, R_(11a) to R_(11h) are defined as R₁₁, R_(12a) to R_(12d) are defined as R₁₂, and * indicates a binding site to an adjacent atom.
 7. The organic light-emitting device of claim 1, wherein the first compound is selected from compounds represented by Formulae 1-1 to 1-3, and the second compound is selected from compounds represented by Formulae 2H-1, 2D-1, and 2D-2, and the third compound comprises a nitrogen-containing heterocyclic group comprising *═N—*′ as a ring forming moiety, and in Formula 3-1, at least one selected from Ar₄₁ to Ar₄₃ is a group selected from groups represented by Formulae A to C, in Formula 3-2, one selected from Ar₄₁ and Ar₄₂ is a group selected from groups represented by Formulae A to C, and the other one selected from Ar₄₁ and Ar₄₂ is a nitrogen-containing heterocyclic group comprising *═N—*′ as a ring-forming moiety:

wherein, in Formulae 1-1, 1-2, 1-3, 2H-1, 2D-1, and 2D-2, L₂₁ to L₂₄, and L₃₁ to L₃₄ are each independently selected from a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group, L₂₅ is selected from a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ non-condensed arylene group, and a substituted or unsubstituted C₁-C₆₀ non-condensed heteroarylene group, L₃₅ is selected from a substituted or unsubstituted C₆-C₆₀ condensed polycyclic arylene group, a substituted or unsubstituted C₁-C₆₀ condensed polycyclic heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group, b1 to b5, and d1 to d5 are each independently an integer selected from 0 to 3, Ar₂₁ to Ar₂₄, and Ar₃₁ to Ar₃₄ are each independently a group selected from groups represented by Formulae A to C, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a biphenyl group, a terphenyl group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, R₂₁ to R₂₄, and R₃₁ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an am idino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, and —Si(Q₄₃)(Q₄₄)(Q₄₅), c1, and c4 are each independently an integer selected from 0 to 4, e1 is an integer selected from 0 to 7, and c2, and c3 are each independently an integer selected from 0 to 3, in Formula 1-1, at least one selected from Ar₂₁ to Ar₂₃ is a group selected from groups represented by Formulae A to C, in Formula 1-2, at least one selected from Ar₂₁ to Ar₂₄ is a group selected from groups represented by Formulae A to C, in Formula 1-3, at least one selected from Ar₂₁ and Ar₂₂ is a group selected from groups represented by Formulae A to C, in Formula 2H-1, Ar₃₁ is a group selected from groups represented by Formulae A to C, in Formula 2D-1, at least one selected from Ar₃₁ to Ar₃₄ is a group selected from groups represented by Formulae A to C, in Formula 2D-2, at least one selected from Ar₃₁ to Ar₃₃ is a group selected from groups represented by Formulae A to C, wherein the group selected from groups represented by Formulae A to C comprises —N(Q₁)(Q₂), and at least one substituent of the substituted C₃-C₁₀ cycloalkylene group, substituted C₁-C₁₀ heterocycloalkylene group, substituted C₃-C₁₀ cycloalkenylene group, substituted C₁-C₁₀ heterocycloalkenylene group, substituted C₆-C₆₀ arylene group, substituted C₆-C₆₀ non-condensed arylene group, substituted C₆-C₆₀ condensed polycyclic arylene group, substituted C₁-C₆₀ heteroarylene group, substituted C₁-C₆₀ non-condensed heteroarylene group, substituted C₁-C₆₀ condensed polycyclic heteroarylene group, substituted divalent non-aromatic condensed polycyclic group, substituted divalent non-aromatic condensed heteropolycyclic group, substituted C₁-C₆₀ alkyl group, substituted C₂-C₆₀ alkenyl group, substituted C₂-C₆₀ alkynyl group, substituted C₁-C₆₀ alkoxy group, substituted C₃-C₁₀ cycloalkyl group, substituted C₁-C₁₀ heterocycloalkyl group, substituted C₃-C₁₀ cycloalkenyl group, substituted C₁-C₁₀ heterocycloalkenyl group, substituted C₆-C₆₀ aryl group, substituted C₆-C₆₀ aryloxy group, substituted C₆-C₆₀ arylthio group, substituted C₁-C₆₀ heteroaryl group, substituted monovalent non-aromatic condensed polycyclic group, and substituted monovalent non-aromatic condensed heteropolycyclic group is selected from: deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group; a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, and —Si(Q₁₃)(Q₁₄)(Q₁₅); a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group; a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group, and —Si(Q₂₃)(Q₂₄)(Q₂₅); and —Si(Q₃₃)(Q₃₄)(Q₃₅), wherein Q₁, Q₂, Q₁₃ to Q₁₅, Q₂₃ to Q₂₅, Q₃₃ to Q₃₅, and Q₄₃ to Q₄₅ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group.
 8. The organic light-emitting device of claim 7, wherein the first compound is selected from compounds represented by Formulae 1-1(1) to 1-1(4), 1-2(1), and 1-3(1), the second compound is selected from compounds represented by Formulae 2H-1(1) to 2H-1(4), 2D-1(1) to 2D-1(4), 2D-2(1), and 2D-2(2), and the third compound is selected from compounds represented by Formulae 3-1(1), 3-1(2), and 3-2(1):

wherein, in Formulae 1-1(1) to 1-1(4), 1-2(1), 1-3(1), 2H-1(1) to 2H-1(4), 2D-1(1) to 2D-1(4), 2D-2(1), 2D-2(2), 3-1(1), 3-1(2), and 3-2(1), Z₁ to Z₅ are each independently selected from: deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group; a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, and —Si(Q₁₃)(Q₁₄)(Q₁₅); a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group; a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, and —Si(Q₂₃)(Q₂₄)(Q₂₅); and —Si(Q₃₃)(Q₃₄)(Q₃₅), wherein Q₁₃ to Q₁₅, Q₂₃ to Q₂₅, and Q₃₃ to Q₃₅ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, f1 is an integer selected from 0 to 4, f2 is an integer selected from 0 to 3, f3 is an integer selected from 0 to 5, and f4 is an integer selected from 0 to 2, in Formula 1-1(1), at least one selected from Ar₂₂ and Ar₂₃ is a group selected from groups represented by Formulae A to C, in Formula 1-1(2), at least one selected from Ar₂₂ and Ar₂₃ is a group selected from groups represented by Formulae A to C, in Formula 1-1(3), at least one selected from Ar₂₁ to Ar₂₃ is a group selected from groups represented by Formulae A to C, in Formula 1-1(4), at least one selected from Ar₂₁ to Ar₂₃ is a group selected from groups represented by Formulae A to C, in Formula 1-2(1), at least one selected from of Ar₂₁ to Ar₂₄ is a group selected from groups represented by Formulae A to C, in Formula 1-3(1), at least one selected from Ar₂₁ and Ar₂₂ is a group selected from groups represented by Formulae A to C, in Formulae 2H-1(1) to 2H-1(4), Ar₃₁ is a group selected from groups represented by Formulae A to C, in Formula 2D-1(1), at least one selected from Ar₃₁ to Ar₃₄ is a group selected from groups represented by Formulae A to C, in Formula 2D-1(2), at least one selected from Ar₃₁ to Ar₃₄ is a group selected from groups represented by Formulae A to C, in Formula 2D-1(3), at least one selected from Ar₃₁ to Ar₃₄ is a group selected from groups represented by Formulae A to C, in Formula 2D-1(4), at least one selected from Ar₃₁ to Ar₃₄ is a group selected from groups represented by Formulae A to C, in Formula 2D-2(1), at least one selected from Ar₃₂ and Ar₃₃ is a group selected from groups represented by Formulae A to C, in Formula 2D-2(2), at least one selected from Ar₃₂ and Ar₃₃ is a group selected from groups represented by Formulae A to C, in Formula 3-1(1), at least one selected from Ar₄₁ to Ar₄₃ is a group selected from groups represented by Formulae A to C, in Formula 3-1(2), at least one selected from Ar₄₁ to Ar₄₃ is a group selected from groups represented by Formulae A to C, and in Formula 3-2(1), one selected from Ar₄₁ and Ar₄₂ is a group selected from groups represented by Formulae A to C, and the other one selected from of Ar₄₁ and Ar₄₂ is a nitrogen-containing heterocyclic group comprising *═N—*′ as a ring forming moiety.
 9. The organic light-emitting device of claim 7, wherein the first compound is selected from compounds represented by Formulae 1-1 to 1-3, and the second compound is represented by Formula 2H-1.
 10. The organic light-emitting device of claim 9, wherein the second layer is an emission layer, the second layer further comprises a dopant, and the first layer and the third layer each directly contact the second layer.
 11. The organic light-emitting device of claim 7, wherein the first compound is selected from compounds represented by Formulae 1-1, 1-2, and 1-3, the second compound is selected from compounds represented by Formulae 2D-1 and 2D-2, and the third compound is selected from compounds represented by Formulae 3-1 and 3-2.
 12. The organic light-emitting device of claim 11, wherein the second layer is an emission layer, the second layer further comprises a host, and the first layer and the third layer each directly contact the second layer.
 13. The organic light-emitting device of claim 1, wherein the first compound is selected from Compounds 1-1 to 1-12 and 2-1 to 2-10, the second compound is selected from Compounds 3-1 to 3-12 and 4-1 to 4-12, and the third compound is selected from Compounds 5-1 to 5-9:


14. An organic light-emitting device comprising: a first electrode; a second electrode facing the first electrode; a first layer between the first electrode and the second electrode, the first layer comprising a first compound; a second layer between the first layer and the second electrode, the second layer comprising a second compound; and a third layer between the second layer and the second electrode, the third layer comprising a third compound; wherein the first compound and the second compound are each independently selected from compounds represented by Formulae 1-1, 1-2, and 1-3, the first compound being different from the second compound, and the third compound is selected from compounds represented by Formulae 2H-1, 2D-1, 2D-2, 3-1, and 3-2:

wherein, in Formulae 1-1, 1-2, 1-3, 2H-1, 2D-1, 2D-2, 3-1, and 3-2, X₁ is C(R₄₁) or N, X₂ is C(R₄₂) or N, X₃ is C(R₄₃) or N, L₂₁ to L₂₄, L₃₁ to L₃₄, and L₄₁ to L₄₃ are each independently selected from a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group, L₂₅ is selected from a substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀ non-condensed arylene group, and a substituted or unsubstituted C₁-C₆₀ non-condensed heteroarylene group, L₃₅ is selected from a substituted or unsubstituted C₆-C₆₀ condensed polycyclic arylene group, a substituted or unsubstituted C₁-C₆₀ condensed polycyclic heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group, b1 to b5, d1 to d5, and g1 to g3 are each independently an integer selected from 0 to 3, Ar₂₁ to Ar₂₄, Ar₃₁ to Ar₃₄, and Ar₄₁ to Ar₄₃ are each independently a group selected from groups represented by Formulae A to C, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a biphenyl group, a terphenyl group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, R₂₁ to R₂₄, R₃₁, and R₄₁ to R₄₄ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an am idino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, and —Si(Q₄₃)(Q₄₄)(Q₄₅), c1, c4, h1, and h4 are each independently an integer selected from 0 to 4, e1 is an integer selected from 0 to 7, and c2, c3, h2, and h3 are each independently an integer selected from 0 to 3, in Formula 1-1, at least one selected from Ar₂₁ to Ar₂₃ is a group selected from groups represented by Formulae A to C, in Formula 1-2, at least one selected from Ar₂₁ to Ar₂₄ is a group selected from groups represented by Formulae A to C, in Formula 1-3, at least one selected from Ar₂₁ and Ar₂₂ is a group selected from groups represented by Formulae A to C, in Formula 2H-1, Ar₃₁ is a group selected from groups represented by Formulae A to C, in Formula 2D-1, at least one selected from Ar₃₁ to Ar₃₄ is a group selected from groups represented by Formulae A to C, in Formula 2D-2, at least one selected from Ar₃₁ to Ar₃₃ is a group selected from groups represented by Formulae A to C, wherein the group selected from groups represented by Formulae A to C comprises —N(Q₁)(Q₂), in Formula 3-1, at least one selected from Ar₄₁ to Ar₄₃ is a group selected from groups represented by Formulae A to C, in Formula 3-2, one selected from Ar₄₁ and Ar₄₂ is a group selected from groups represented by Formulae A to C, and the other one selected from Ar₄₁ and Ar₄₂ is a nitrogen-containing heterocyclic group comprising *═N—*′ as a ring forming moiety,

wherein, in Formulae A to C, ring A₁, ring A₁₁, and ring A₁₂ are each independently selected from a C₅-C₃₀ carbocyclic group and a C₂-C₃₀ heterocyclic group, R₁, R₂, R₁₁, and R₁₂ are each independently selected from: hydrogen, deuterium, —F, —Cl, —Br, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group; a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, and a phosphoric acid group or a salt thereof; a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group; a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group; and —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), and —B(Q₆)(Q₇), wherein Q₁ to Q₇ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, a1, a11, and a12 are each independently an integer selected from 0 to 10, a2 is an integer selected from 0 to 2, and wherein * and *¹ each indicate a binding site to an adjacent atom, and at least one substituent of the substituted C₃-C₁₀ cycloalkylene group, substituted C₁-C₁₀ heterocycloalkylene group, substituted C₃-C₁₀ cycloalkenylene group, substituted C₁-C₁₀ heterocycloalkenylene group, substituted C₆-C₆₀ arylene group, substituted C₆-C₆₀ non-condensed arylene group, substituted C₆-C₆₀ condensed polycyclic arylene group, substituted C₁-C₆₀ heteroarylene group, substituted C₁-C₆₀ non-condensed heteroarylene group, substituted C₁-C₆₀ condensed polycyclic heteroarylene group, substituted divalent non-aromatic condensed polycyclic group, substituted divalent non-aromatic condensed heteropolycyclic group, substituted C₁-C₆₀ alkyl group, substituted C₂-C₆₀ alkenyl group, substituted C₂-C₆₀ alkynyl group, substituted C₁-C₆₀ alkoxy group, substituted C₃-C₁₀ cycloalkyl group, substituted C₁-C₁₀ heterocycloalkyl group, substituted C₃-C₁₀ cycloalkenyl group, substituted C₁-C₁₀ heterocycloalkenyl group, substituted C₆-C₆₀ aryl group, substituted C₆-C₆₀ aryloxy group, substituted C₆-C₆₀ arylthio group, substituted C₁-C₆₀ heteroaryl group, substituted monovalent non-aromatic condensed polycyclic group, and substituted monovalent non-aromatic condensed heteropolycyclic group is selected from: deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group; a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, and —Si(Q₁₃)(Q₁₄)(Q₁₅); a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group; a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group, and —Si(Q₂₃)(Q₂₄)(Q₂₅); and —Si(Q₃₃)(Q₃₄)(Q₃₅), wherein Q₁, Q₂, Q₁₃ to Q₁₅, Q₂₃ to Q₂₅, Q₃₃ to Q₃₅, and Q₄₃ to Q₄₅ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group.
 15. The organic light-emitting device of claim 14, wherein the first compound and the second compound are each independently selected from compounds represented by Formulae 1-1(1) to 1-1(4), 1-2(1), and 1-3(1), and the third compound is selected from compounds represented by Formulae 2H-1(1) to 2H-1(4), 2D-1(1) to 2D-1(4), 2D-2(1), 2D-2(2), 3-1(1), 3-1(2), and 3-2(1):

wherein, in Formulae 1-1(1) to 1-1(4), 1-2(1), 1-3(1), 2H-1(1) to 2H-1(4), 2D-1(1) to 2D-1(4), 2D-2(1), 2D-2(2), 3-1(1), 3-1(2), and 3-2(1), Z₁ to Z₅ are each independently selected from: deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group; a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, and —Si(Q₁₃)(Q₁₄)(Q₁₅); a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group; a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, and —Si(Q₂₃)(Q₂₄)(Q₂₅); and —Si(Q₃₃)(Q₃₄)(Q₃₅), wherein Q₁₃ to Q₁₅, Q₂₃ to Q₂₅, and Q₃₃ to Q₃₅ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, f1 is an integer selected from 0 to 4, f2 is an integer selected from 0 to 3, f3 is an integer selected from 0 to 5, and f4 is an integer selected from 0 to 2, in Formula 1-1(1), at least one selected from Ar₂₂ and Ar₂₃ is a group selected from groups represented by Formulae A to C, in Formula 1-1(2), at least one selected from Ar₂₂ and Ar₂₃ is a group selected from groups represented by Formulae A to C, in Formula 1-1(3), at least one selected from Ar₂₁ to Ar₂₃ is a group selected from groups represented by Formulae A to C, and in Formula 1-1(4), at least one selected from Ar₂₁ to Ar₂₃ is a group selected from groups represented by Formulae A to C, and in Formula 1-2(1), at least one selected from Ar₂₁ to Ar₂₄ is a group selected from groups represented by Formulae A to C, and in Formula 1-3(1), at least one selected from Ar₂₁ and Ar₂₂ is a group selected from groups represented by Formulae A to C, in Formulae 2H-1(1) to 2H-1(4), Ar₃₁ is a group selected from groups represented by Formulae A to C, in Formula 2D-1(1), at least one o selected from f Ar₃₁ to Ar₃₄ is a group selected from groups represented by Formulae A to C, in Formula 2D-1(2), at least one selected from Ar₃₁ to Ar₃₄ is a group selected from groups represented by Formulae A to C, in Formula 2D-1(3), at least one selected from Ar₃₁ to Ar₃₄ is a group selected from groups represented by Formulae A to C, in Formula 2D-1(4), at least one selected from Ar₃₁ to Ar₃₄ is a group selected from groups represented by Formulae A to C, in Formula 2D-2(1), at least one selected from Ar₃₂ and Ar₃₃ is a group selected from groups represented by Formulae A to C, in Formula 2D-2(2), at least one selected from Ar₃₂ and Ar₃₃ is a group selected from groups represented by Formulae A to C, in Formula 3-1(1), at least one selected from Ar₄₁ to Ar₄₃ is a group selected from groups represented by Formulae A to C, in Formula 3-1(2), at least one selected from Ar₄₁ to Ar₄₃ is a group selected from groups represented by Formulae A to C, and in Formula 3-2(1), one selected from Ar₄₁ and Ar₄₂ is a group selected from groups represented by Formulae A to C, and the other one selected from Ar₄₁ and Ar₄₂ is a nitrogen-containing heterocyclic group comprising *═N—*′ as a ring forming moiety.
 16. The organic light-emitting device of claim 14, wherein the first compound and the second compound are each independently selected from compounds represented by Formulae 1-1, 1-2, and 1-3, the first compound being different from the second compound, and the third compound is selected from compounds represented by Formulae 2H-1, 3-1, and 3-2.
 17. The organic light-emitting device of claim 16, wherein the third layer is an emission layer, the third layer further comprises a dopant, and the second layer directly contacts the third layer.
 18. The organic light-emitting device of claim 14, wherein the first compound and the second compound are each independently selected from compounds represented by Formulae 1-1, 1-2, and 1-3, the first compound being different from the second compound, and the third compound is selected from compounds represented by Formulae 2D-1 and 2D-2.
 19. The organic light-emitting device of claim 18, wherein the third layer is an emission layer, the third layer further comprises a host, and the second layer directly contacts the third layer.
 20. An organic light-emitting device comprising: a first electrode; a second electrode facing the first electrode; a first layer between the first electrode and the second electrode, the first layer comprising a first compound; a second layer between the first layer and the second electrode, the second layer comprising a second compound; and a third layer between the second layer and the second electrode, the third layer comprising a third compound; wherein the first compound and the second compound are each independently selected from Compounds 1-1 to 1-12 and 2-1 to 2-10, the first compound being different from the second compound, and the third compound is selected from Compounds 3-1 to 3-12, 4-1 to 4-12, and 5-1 to 5-9: 